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A common problem in many factories is simple to understand but difficult to solve on-site: the PLC, controller, energy meter, weigh indicator, data logger or remote field device has a serial port, but the control room is far away. Pulling a new RS-485 or RS-232 cable may be expensive, unsafe, time-consuming or physically impossible.

This is where wireless serial converters become useful.

Instead of running long serial cables across machines, panels, utilities or shop floors, a wireless serial converter helps transmit RS-232 / RS-422 / RS-485 data over RF, Zigbee or WiFi depending on the model and application.

For buyers, the main question is not only “Which converter is cheaper?” The real question is:

Which wireless serial converter will work reliably with my distance, communication interface, baud rate, power supply, PLC/SCADA system and site environment?

For Radical TechMart buyers comparing ATC-871 / ATC-873 / ATC-875, ATC-3200 and ATC-2000WF, this guide explains how to select the right model for actual industrial use.

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What are Wireless Serial Converters?

A wireless serial converter is a communication device that converts wired serial communication such as RS-232, RS-422 or RS-485 into a wireless communication path.

In simple words, it acts like a bridge between a serial device and a wireless network.

For example:

• RS-485 device to RF link
• RS-232 controller to wireless receiver
• RS-485 Modbus meter to SCADA system
• Serial machine data to WiFi network
• PLC serial port to remote HMI or monitoring software

These converters are commonly used when serial communication is required but cable laying is difficult, costly or impractical.

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Why Wireless Serial Communication Matters in Actual Plant Conditions

In actual plant conditions, communication problems usually appear during commissioning or maintenance.

A machine may be installed far from the control room. A weighbridge may be located outdoors. A utility meter may be inside a remote panel. A PLC may need to exchange data with another controller across a production area.

If communication wiring is not planned properly, the site team may face:

• Long cable routing delays
• RS-485 signal drop or noise issues
• Extra cable tray and conduit cost
• Difficulty in connecting moving or rotating equipment
• Outdoor cable damage
• Grounding and electrical noise problems
• Downtime during cable replacement
• Weak communication between PLC, SCADA, HMI or data logger

A wireless serial converter can reduce these problems when selected correctly. But wrong selection can create new problems like poor range, unstable data transfer, wrong interface matching or software compatibility issues.

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How Wireless Serial Converters Work

A wireless serial converter receives data from a wired serial port such as RS-232, RS-422 or RS-485. It then transmits that data using a wireless medium such as RF, Zigbee or WiFi.

At the receiving end, another converter or network device converts the signal back into a usable serial or network communication format.

A typical communication path may look like this:

PLC / Meter / Controller → RS-485 / RS-232 Port → Wireless Serial Converter → RF / Zigbee / WiFi Link → SCADA / HMI / PC / Remote Device

The important point is that the converter must match:

• The serial interface
• Communication speed
• Wireless technology
• Distance requirement
• Power supply
• Software or network requirement
• Site environment

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Types of Wireless Serial Converters in this Category

1. Serial to RF Converter – ATC-871 / ATC-873 / ATC-875

The ATC-871 / ATC-873 / ATC-875 type is suitable when a serial signal needs to be transmitted wirelessly using RF communication. This is useful where the user wants a dedicated wireless serial link instead of depending on factory WiFi.

Technical points to note:

• Interface: RS-232 / RS-422 / RS-485
• Carrier frequency: 433 MHz
• Field interface: Radio frequency
• Channels: Up to 8 channels
• Transmission rate: 1.2 kbps to 38.4 kbps
• Indication LED: Sending data red / receiving data green
• Transmission distance options: 300 m, 500 m, 800 m, 2000 m at 9.6 kbps
• Power supply: 9–24 VDC external adaptor supply

Where it is commonly used:

• Remote RS-485 meter communication
• PLC-to-PLC low-speed serial communication
• Utility monitoring panels
• Machine data transfer where cable routing is difficult
• Outdoor or semi-outdoor equipment communication
• Factory automation points requiring wireless serial link

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2. RS-232 / RS-422 / RS-485 to Zigbee Converter – ATC-3200

The ATC-3200 is suitable when a serial device needs to communicate using Zigbee-based wireless transmission. This type is useful for applications where low-power wireless networking and short-to-medium range device communication are required.

Technical points to note:

• Interface: RS-232 / RS-422 / RS-485
• Wireless standard: IEEE 802.15.4 compliant
• Typical receiver sensitivity: 102 dBm
• Transmission rate: Typical throughput rate 250 kbps
• Indication LED: Sending data red / receiving data green
• Wireless band: Globally available 2.4 GHz ISM band
• Power supply: 9–24 VDC external adaptor supply

Where it is commonly used:

• Wireless sensor or controller networking
• Remote data acquisition points
• Automation panels where short-distance wireless communication is preferred
• Machine monitoring systems
• Energy monitoring or utility data collection
• OEM automation projects requiring wireless device communication

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3. WiFi to Serial Converter – ATC-2000WF

The ATC-2000WF is suitable when a serial device needs to connect into a WiFi or Ethernet-style network environment. This model is useful when plant data needs to move from a serial device to PC software, virtual COM port software, monitoring systems or network-based applications.

Technical points to note:

• Interface: Compatible with EIA RS-232C and RS-485 standard
• Supported wireless modes: Ad-hoc, infrastructure and pseudo IBSS mode support
• Transmission rate: Auto-negotiating 10/100 Mbps Ethernet
• Software support: Vports software and other virtual serial port software
• Indication LED: Sending data red / receiving data green
• Distance: 1000 feet in open environment
• Power supply: 9–24 VDC external adaptor supply

Where it is commonly used:

• Serial device connection to PC software
• RS-485 device monitoring over WiFi
• Data logging and remote parameter monitoring
• SCADA or HMI network integration
• Utility meter or controller communication
• Retrofit automation where serial cabling is difficult

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Quick Comparison: ATC-871 / 873 / 875 vs ATC-3200 vs ATC-2000WF

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Key Selection Factors for Wireless Serial Converters

1. Serial Interface Type

First confirm whether the field device has:

• RS-232
• RS-422
• RS-485

This is the first selection point. A wrong interface selection means the converter may not communicate with the field device at all.

RS-232 is generally point-to-point. RS-485 is commonly used for multi-drop industrial communication. RS-422 is used in selected full-duplex communication applications.

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2. Wireless Technology

Choose the wireless type based on application:

• RF converter: Better for dedicated serial wireless link
• Zigbee converter: Better for low-power device networking
• WiFi converter: Better when serial data needs to connect with network or PC software

Do not select wireless technology only by availability. Select it based on plant layout, communication requirement and system architecture.

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3. Distance Requirement

Distance is not only the number written in the specification. Actual distance depends on:

• Line of sight
• Walls and machinery
• Electrical noise
• Antenna position
• Cable and panel location
• Outdoor or indoor environment
• Baud rate and data stability requirement

For example, an open-environment distance will not always be achieved inside a factory full of machines, panels and metal structures.

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4. Baud Rate and Data Load

Check the baud rate of the connected device. Some serial devices use 9600 bps, while others may use higher speeds.

If the converter supports the required interface but not the required data speed, communication can become unstable.

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5. Power Supply

Most industrial panels commonly use 24 VDC instrumentation power. The models discussed here use 9–24 VDC external adaptor supply, so confirm the available panel power and adaptor requirement before purchase.

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6. PLC / SCADA / HMI Compatibility

Before selecting the converter, check:

• Does the PLC communicate on RS-232, RS-485 or RS-422?
• Is the protocol Modbus RTU or another serial protocol?
• Does SCADA need a COM port or IP-based connection?
• Is virtual COM software required?
• Is the system master-slave or peer-to-peer?

Wireless serial conversion should not disturb the protocol structure.

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7. Site Environment

Industrial wireless communication can be affected by:

• Metal panels
• Motor drives
• VFD electrical noise
• Welding machines
• Heavy machinery
• Thick walls
• Long distance between buildings
• Outdoor weather exposure

Always check installation conditions before finalizing the model.

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Common Applications of Wireless Serial Converters

Wireless serial converters are commonly used in:

• PLC to remote device communication
• SCADA data collection from remote RS-485 devices
• HMI communication with serial controllers
• Wireless utility meter monitoring
• Weighbridge and weighing system communication
• Boiler, compressor and pump room monitoring
• Water treatment plant remote panels
• Packaging and production machine data transfer
• OEM machine communication
• Retrofitting old serial devices into modern monitoring systems

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Common Mistakes to Avoid

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Do This, Not That

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Quick Selection Checklist

Before selecting a wireless serial converter, confirm these points:

1. What is the field interface — RS-232, RS-422 or RS-485?
2. What is the communication protocol — Modbus RTU or another serial protocol?
3. What baud rate is required?
4. What distance is required between devices?
5. Is the communication point-to-point or network-based?
6. Is RF, Zigbee or WiFi better for the application?
7. Is 9–24 VDC power available near the installation point?
8. Does the system need virtual COM port software?
9. Will the converter connect to PLC, SCADA, HMI, PC or another controller?
10. Are there obstacles, electrical noise or metal structures between communication points?

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Product Selection Guide

Choose ATC-871 / ATC-873 / ATC-875 when:

• You need serial to RF communication
• Your device uses RS-232 / RS-422 / RS-485
• You need a dedicated wireless serial link
• The application is not dependent on plant WiFi
• Distance and line-of-sight planning can be done properly

This model family is useful for plant-level serial communication where cable laying is difficult and RF transmission is preferred.-

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Choose ATC-3200 when:

• You need Zigbee-based wireless communication
• Your system supports RS-232 / RS-422 / RS-485 interface
• You want 2.4 GHz ISM band communication
• The application involves device networking or low-power wireless communication
• The installation can support Zigbee communication conditions

This model makes sense where Zigbee communication fits the automation architecture.

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Choose ATC-2000WF when:

• You need WiFi to serial communication
• You want RS-232C / RS-485 devices to communicate through network-based software
• PC monitoring or virtual COM software is required
• Existing network infrastructure is available
• The application needs serial device access over WiFi or Ethernet-style communication

This model is better when the user wants serial data to move into software or network-based monitoring systems.

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Specifications to Confirm Before Purchase

Before finalizing any wireless serial converter, confirm:

• Serial interface: RS-232 / RS-422 / RS-485
• Wireless type: RF / Zigbee / WiFi
• Baud rate requirement
• Transmission distance
• Indoor or outdoor installation condition
• Power supply requirement
• Antenna and mounting position
• Protocol compatibility
• PLC / SCADA / HMI compatibility
• Virtual COM software requirement
• Master-slave communication logic
• Site electrical noise condition
• Number of devices in communication network
• Datasheet and wiring diagram
• Availability, pricing and delivery timeline

Specifications may vary depending on model and manufacturer. Please confirm the datasheet before final selection.

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Why Buy Wireless Serial Converters from Radical TechMart?

At Radical TechMart, the focus is not only to supply the product, but to help customers select the right communication device for the right application.

For wireless serial converters, proper selection matters because one wrong assumption can create communication failure during commissioning. A purchase team may compare price, but the maintenance and automation team will face the result of wrong selection.

Radical TechMart can support buyers with:

• Wireless serial converter selection
• RS-232 / RS-485 / RS-422 communication product guidance
• PLC, HMI and SCADA communication requirement discussion
• Product availability and pricing support
• Datasheet and technical inquiry support
• Support for OEMs, panel builders, factories and system integrators

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Final Thoughts

Wireless serial converters are useful when industrial communication needs to move beyond cable limitations. But they should not be selected casually.

The correct model depends on the interface, wireless method, distance, baud rate, protocol, power supply and control system compatibility.

For a simple RF serial link, ATC-871 / ATC-873 / ATC-875 may be suitable. For Zigbee-based serial networking, ATC-3200 can be considered. For WiFi or network-based serial communication, ATC-2000WF is the better direction.

In industrial applications, the right communication product is not selected only by price or model number. It is selected by understanding the device, the signal, the distance, the environment and the final control requirement.

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FAQs

1. What is a wireless serial converter?

A wireless serial converter is a device that converts RS-232, RS-422 or RS-485 serial communication into wireless communication using RF, Zigbee or WiFi.

2. Which wireless serial converter is suitable for RS-485 communication?

It depends on the wireless method required. ATC-871 / ATC-873 / ATC-875 can be used for RF-based serial communication, ATC-3200 for Zigbee-based serial communication, and ATC-2000WF for WiFi to serial communication.

3. Can wireless serial converters connect with PLC and SCADA?

Yes, they can be used with PLC and SCADA systems if the serial interface, baud rate, communication protocol and software configuration are compatible.

4. What is the difference between RF and WiFi serial converters?

RF serial converters are generally used for dedicated wireless serial links. WiFi serial converters are used when serial devices need to connect through WiFi or network-based software.

5. Is ATC-2000WF suitable for virtual COM port applications?

ATC-2000WF supports virtual serial port software, making it suitable for applications where PC software needs to communicate with serial devices over a network.

6. What should be checked before buying a wireless serial converter?

Check serial interface, baud rate, wireless range, protocol, power supply, site environment, PLC/SCADA compatibility and datasheet before purchase.

7. Can wireless serial converters be used for Modbus RTU?

Yes, they can be used for Modbus RTU communication if the converter supports the required serial interface and baud rate, and the wireless link is stable enough for the application.

8. Which is better: RF, Zigbee or WiFi?

There is no single best option. RF is useful for dedicated wireless serial links, Zigbee is useful for device networking, and WiFi is useful when serial data needs to connect with network or PC software.

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In many industrial plants, communication problems do not always start with the PLC, SCADA, HMI, or field device. Very often, the real issue is the gap between old serial communication and modern Ethernet-based systems.

One machine may still communicate through RS-232. Another device may use RS-485 Modbus RTU. A new SCADA system may expect Ethernet. A remote site may need GSM-based communication. When these systems are not connected properly, the result is data loss, unstable monitoring, delayed troubleshooting, and unnecessary downtime.

That is where Ethernet / Modbus gateways and converters become important. These devices help connect serial devices, PLCs, meters, controllers, data loggers, HMIs, and SCADA systems into a more usable industrial communication network.

For buyers comparing models such as ATC-3000, ATC-1300, and ATC-1200, the right selection depends on one key question:

Are you converting serial data to Ethernet, connecting Modbus devices, or enabling remote GSM communication?

Let’s break it down in a practical way.

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What Is an Ethernet / Modbus Gateway?

An Ethernet / Modbus gateway is a communication device that helps different industrial devices talk to each other even when they use different interfaces or protocols.

For example, many field instruments and controllers use:

• RS-232
• RS-485
• RS-422
• Modbus RTU
• Serial communication

But modern systems often require:

• Ethernet
• Modbus TCP/IP
• LAN connectivity
• SCADA integration
• Remote monitoring

A gateway or converter works as a bridge between these systems.

In actual plant conditions, this is useful when an existing machine, controller, or meter is still working properly but needs to be connected to a newer Ethernet-based automation system. Instead of replacing the entire system, a suitable gateway can extend the life of existing equipment.

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Why These Gateways Matter in Industrial Automation

In industrial automation, communication is not just about data transfer. It affects production visibility, alarm monitoring, process control, maintenance response, and decision-making.

A properly selected gateway can help:

• Connect legacy RS-232 / RS-485 / RS-422 devices to Ethernet
• Integrate field instruments with PLC, HMI, or SCADA
• Enable remote monitoring of serial devices
• Reduce manual data collection
• Improve troubleshooting from a central system
• Support machine upgrades without replacing all existing devices
• Create a cleaner communication architecture for panel builders and system integrators

The wrong gateway, however, can create repeated communication failure. Common issues include wrong baud rate, unsupported serial interface, incorrect wiring, protocol mismatch, unstable power supply, or using a converter where a true gateway is required.

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Product Selection: ATC-3000 vs ATC-1300 vs ATC-1200

1. ATC-3000 – 1-Port Modbus Gateway

The ATC-3000 is suitable when a plant needs to connect serial Modbus or serial field devices to an Ethernet network. It is especially useful for PLC, SCADA, HMI, energy meter, controller, or data acquisition applications where serial field communication needs to move into an Ethernet environment.

This model makes sense when the requirement is not only simple physical conversion, but also structured gateway-type communication between serial and Ethernet systems.

Technical points to note:

• Product type: 1-port Modbus gateway
• Computer interface: RJ-45 Ethernet
• Field interface: 3-in-1 RS-232 / RS-422 / RS-485 interface
• Serial transmission rate: 230 kbps
• Ethernet transmission: 10/100 Mbps
• Configuration options: Webpage, Telnet, serial console, Windows utility
• Indication LED: Sending data red, receiving data green
• Power supply: 9–24 VDC external adapter supply
• OS support: Windows 98 / ME / XP / 2000 / 7 / 8, Mac, Linux

Where it is commonly used:

• PLC to SCADA communication
• Modbus RTU device to Ethernet network integration
• Energy meter monitoring
• Industrial controller networking
• Machine data collection
• Panel-based automation systems

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2. ATC-1300 – Modbus Gateway with GPRS / UART Support

The ATC-1300 is suitable when communication is required beyond a local plant network. It is useful for remote monitoring applications where serial devices need to transmit data through GSM / GPRS-based communication.

This model is more relevant when the installation is not limited to a LAN or factory floor. For water treatment, utilities, remote pump houses, energy monitoring, or unmanned sites, GSM-based communication can help send data where wired Ethernet is not practical.

Technical points to note:

• Product type: Modbus gateway
• Interface: RS-232 / RS-485 optional
• Communication support: Two-way GPRS and UART interface
• GSM frequency range: 850 / 900 / 1800 / 1900 MHz
• Baud rate: 1200 to 115.2 kbps
• Remote function: Sleep and wake-up support through local serial port
• SIM card support: Standard 3.3V / 1.8V USAR card interface
• GPRS speed: Upload 1–2 kbps, download 3–4 kbps

Where it is commonly used:

• Remote pump stations
• Water and wastewater monitoring
• Utility metering
• Remote machine monitoring
• Agricultural automation panels
• Remote data collection from serial instruments

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3. ATC-1200 – RS-232 / RS-422 / RS-485 to Ethernet Converter

The ATC-1200 is suitable when the main requirement is to convert serial communication into Ethernet connectivity. This is useful for connecting existing serial devices to a network without changing the device itself.

This model is a practical choice for system integrators and maintenance teams who need to bring legacy equipment into an Ethernet-based monitoring system.

Technical points to note:

• Product type: RS-232 / RS-422 / RS-485 to Ethernet converter
• Computer interface: RJ-45 Ethernet
• Field interface: 3-in-1 RS-232 / RS-422 / RS-485 interface
• Serial transmission rate: 230 kbps
• Ethernet transmission: 10/100 Mbps
• Indication LED: Sending data red, receiving data green
• Configuration support: IP configuration by MAC address
• Power supply: 9–24 VDC external adapter supply
• OS support: Windows 98 / ME / XP / 2000 / 7 / 8, Mac, Linux

Where it is commonly used:

• Serial machine connection to Ethernet
• RS-485 field device networking
• Old controller integration with PC software
• Data logger connectivity
• Industrial panel communication upgrades
• SCADA-ready serial device conversion

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Quick Comparison: ATC-3000 vs ATC-1300 vs ATC-1200

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How to Select the Right Ethernet / Modbus Gateway

1. Confirm the Field Interface

First check what your device actually supports:

• RS-232
• RS-485
• RS-422

Do not assume all serial communication is the same. RS-232 is commonly point-to-point, while RS-485 is preferred for longer-distance multi-drop industrial communication.

2. Confirm the Network Side

If the system must connect to a local Ethernet network, consider ATC-3000 or ATC-1200. If the application is remote and GSM-based communication is required, ATC-1300 becomes more relevant.

3. Check Protocol Requirement

A converter and a gateway are not always the same thing.

A converter may change the physical interface from serial to Ethernet. A gateway may also handle protocol-level communication between Modbus RTU and Ethernet-based systems.

Before purchase, confirm whether your PLC, SCADA, or software expects:

• Raw serial over Ethernet
• Virtual COM port
• Modbus RTU
• Modbus TCP/IP
• GPRS data transfer

4. Match Baud Rate and Serial Settings

Always confirm:

• Baud rate
• Parity
• Data bits
• Stop bits
• Slave ID
• Master / slave role
• Half duplex or full duplex requirement

Many communication failures happen because the hardware is correct but the serial settings are not matched.

5. Confirm Power Supply

ATC-3000 and ATC-1200 use 9–24 VDC external adapter supply. This is important for panel design because many industrial panels already have 24 VDC instrumentation power. Still, the actual adapter and wiring arrangement should be confirmed before installation.

6. Consider the Installation Environment

Before finalizing, check:

• Panel space
• Mounting arrangement
• Electrical noise
• Cable length
• Shielding and grounding
• Surge protection requirement
• Network accessibility
• Maintenance access

For harsh industrial locations, enclosure and wiring practices matter as much as the communication converter itself.

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Common Applications

Ethernet / Modbus gateways and converters are commonly used in:

• PLC and SCADA integration
• HMI communication
• Energy meter data monitoring
• RS-485 Modbus RTU networks
• Pump house monitoring
• Water treatment automation
• Machine data collection
• Industrial controller networking
• Remote utility monitoring
• OEM machine panels
• Retrofitting old machines with Ethernet connectivity
• Data acquisition systems

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Common Mistakes to Avoid

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Quick Selection Checklist Before Purchase

Before selecting ATC-3000, ATC-1300, or ATC-1200, confirm:

• What is the field interface: RS-232, RS-485, or RS-422?
• Is the requirement local Ethernet or remote GSM / GPRS?
• Does the application need Modbus gateway functionality or simple serial-to-Ethernet conversion?
• What is the baud rate and serial setting?
• Is the device communicating with PLC, HMI, SCADA, PC software, or data logger?
• Is the required power supply available in the panel?
• Is the installation indoor, panel-mounted, or remote field-mounted?
• Is continuous data transfer required or only periodic data logging?
• Is technical support required for configuration?
• Are datasheet and compatibility details confirmed before purchase?

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Why Buy Ethernet / Modbus Gateways from Radical TechMart?

Radical TechMart helps industrial buyers select products based on actual application requirements, not only model numbers.

For communication products, this matters because the wrong selection can waste commissioning time. A buyer may know that they need an “RS485 Ethernet converter,” but the real selection depends on PLC protocol, SCADA software, wiring distance, serial settings, power supply, and whether the system needs gateway-level communication.

Radical TechMart can help with:

• Model selection support
• Datasheet guidance
• Application matching
• Compatibility discussion
• Industrial communication product sourcing
• Support for automation, instrumentation, and panel requirements

In industrial communication, the right converter is not selected only by port type. It is selected by understanding the device, protocol, network, wiring, software, and final monitoring requirement.

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FAQs

1. What is the difference between ATC-3000 and ATC-1200?

ATC-3000 is positioned as a 1-port Modbus gateway, while ATC-1200 is an RS-232 / RS-422 / RS-485 to Ethernet converter. Choose ATC-3000 when Modbus gateway functionality is required. Choose ATC-1200 when the requirement is mainly serial-to-Ethernet conversion. Final compatibility should be confirmed based on PLC, SCADA, and device protocol.

2. When should I choose ATC-1300?

Choose ATC-1300 when the application needs GPRS / UART-based remote communication. It is suitable for remote sites where wired Ethernet is difficult, such as pump stations, utility panels, remote meters, or field monitoring points.

3. Can these devices connect RS-485 instruments to SCADA?

Yes, models like ATC-3000 and ATC-1200 can support RS-485 field interface connectivity. However, SCADA compatibility depends on whether the software requires Modbus RTU, Modbus TCP/IP, virtual COM port, or another communication method.

4. Is RS-485 better than RS-232 for industrial applications?

RS-485 is generally preferred for longer distance and multi-device industrial communication. RS-232 is usually better for shorter point-to-point communication. The final choice depends on the connected device and wiring requirement.

5. What should I confirm before buying a Modbus gateway?

Confirm the serial interface, protocol, baud rate, parity, power supply, Ethernet requirement, software compatibility, distance, and whether the device must work as a gateway or only as a converter.

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A plant engineer usually does not search for a USB to serial converter when everything is working smoothly.

He searches when the laptop has no COM port, the old machine still has RS-232, the energy meter communicates through RS-485, the PLC needs serial configuration, or a Modbus RTU network has to be checked from a service laptop.

This is where USB to Serial Converters become important.

In industrial automation, serial communication has not disappeared. Many controllers, meters, indicators, VFDs, weighing systems, data loggers, PLCs, HMIs, and legacy machines still depend on RS-232, RS-485, RS-422, or TTL communication. Modern laptops, however, usually provide USB ports instead of built-in serial ports.

A USB to serial converter bridges that gap.

But the main mistake buyers make is assuming every USB converter is the same. A USB to RS-232 converter is not the same as a USB to RS-485 converter. A TTL converter is not suitable for RS-232 wiring. An isolated converter is different from a basic converter. A single-port converter is different from a 4-port RS-232 converter.

This guide explains how to choose the right ATC USB to Serial Converter from the following models:

• ATC-840
• ATC-810
• ATC-850
• ATC-820
• ATC-804
• ATC-830

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What are USB to Serial Converters?

USB to Serial Converters are communication interface devices that allow a USB port on a computer or laptop to communicate with serial devices.

In simple words, they create a virtual COM port on the computer so software can communicate with industrial devices through RS-232, RS-485, RS-422, or TTL.

They are commonly used for:

• PLC programming
• HMI configuration
• VFD parameter setting
• Modbus RTU communication
• Energy meter reading
• Data logger communication
• Machine diagnostics
• Controller configuration
• Serial device testing
• Legacy equipment communication

A USB converter may look like a small cable or module, but in actual plant conditions, its selection affects communication stability, troubleshooting time, and field commissioning speed.

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Why USB to Serial Converters Matter in Actual Plant Conditions

In actual plant conditions, serial communication failure can waste hours.

The software may show “COM port not found.” The PLC may not respond. The Modbus polling software may show timeout errors. The laptop may detect the converter, but the connected device may still not communicate. Sometimes the issue is not the PLC or controller at all — it is the wrong converter type.

A wrong USB to serial converter can create:

• No communication with PLC, HMI, or meter
• Wrong signal level between USB and field device
• Driver installation issues
• Unstable COM port detection
• Communication timeout in Modbus RTU
• Data loss in noisy industrial areas
• Damage risk when TTL and RS-232 are confused
• Commissioning delays at site

A purchase team may compare only price, but the automation engineer has to face the result during commissioning.

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How USB to Serial Converters Work

A USB to serial converter connects to the computer through USB and appears as a COM port after driver installation. The converter then translates USB data into the required serial interface.

For example:

• USB to RS-232 for old controllers, machines, and serial instruments
• USB to RS-485 for Modbus RTU networks and multi-drop devices
• USB to RS-422 for full-duplex differential communication
• USB to TTL for embedded boards and logic-level serial devices
• Isolated USB to serial for noisy industrial environments

The converter does not automatically fix wrong serial settings. Baud rate, parity, data bits, stop bits, wiring polarity, and protocol settings must still match the connected device.

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Types of USB to Serial Converters

ATC-840 – RS-422 to USB Converter

ATC-840 is suitable when a computer or laptop needs to communicate with an RS-422 device through USB. This model is useful where RS-422 full-duplex communication is required.

Technical points to note:

• Computer interface: USB 2.0 plug and play
• Operating system support: Windows 98 / ME / XP / 2000 / Vista / 7 / 8, Mac and Linux reference
• Field interface: RS-422 full duplex
• Transmission rate: 300 bps to 1 Mbps reference
• Indication LED: sending data red and receiving data green
• Connector: DB9 male connector for RS-422 with terminal block
• Power: from USB port

Where it is commonly used:

• RS-422 machine communication
• Industrial controller configuration
• Legacy equipment diagnostics
• Full-duplex serial communication
• Factory automation service laptops
• Serial data testing

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ATC-810 – RS-232 to USB Converter

ATC-810 is suitable when a laptop or computer needs to communicate with an RS-232 device. This is one of the most common needs in industrial service and maintenance work.

Technical points to note:

• Computer interface: USB 2.0 plug and play
• Operating system support: Windows 98 / ME / XP / 2000 / Vista / 7 / 8, Mac and Linux reference
• Chipset reference: FTDI chipset for industrial area
• Transmission rate: over 460 kbps reference
• Indication LED: sending data red and receiving data green
• Connector: DB9 male connector for RS-232
• Power: from USB port

Where it is commonly used:

• PLC programming
• HMI configuration
• Controller parameter setup
• Weighing scale communication
• Machine tool communication
• RS-232 data logging

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ATC-850 – Isolated RS-232/422/485 to USB Converter

ATC-850 is suitable when a single USB converter must support multiple serial standards with isolation. This is the most flexible option in this USB-to-serial group.

Technical points to note:

• Computer interface: USB 2.0 plug and play
• Operating system support: Windows 98 / ME / XP / 2000 / Vista / 7 / 8, Mac and Linux reference
• Field interface: full-duplex RS-232; RS-485/422 half-duplex reference
• Transmission rate: 300 bps to 1 Mbps reference
• Indication LED: sending data red and receiving data green
• Isolation: 3500 VRMS / 500 VDC sequence reference
• Power: external 9 VDC power supply from adapter

Where it is commonly used:

• PLC / SCADA troubleshooting
• Multi-standard serial communication testing
• Noisy panel environments
• RS-485 Modbus RTU networks
• RS-232 machine diagnostics
• Service kits for automation engineers

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ATC-820 – RS-485 to USB Converter

ATC-820 is suitable when a laptop or computer needs to connect to an RS-485 network. This is especially useful for Modbus RTU communication, energy meters, controllers, transmitters, and multi-drop serial devices.

Technical points to note:

• Computer interface: USB 2.0 plug and play
• Operating system support: Windows 98 / ME / XP / 2000 / Vista / 7 / 8, Mac and Linux reference
• Field interface: half duplex RS-485
• Transmission rate: 300 bps to 1 Mbps reference
• Indication LED: sending data red and receiving data green
• Connector: DB9 male connector for RS-485 with terminal block
• Power: from USB port

Where it is commonly used:

• Modbus RTU testing
• Energy meter communication
• RS-485 transmitter configuration
• PLC to field device troubleshooting
• Data logger communication
• Multi-drop serial network checking

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ATC-804 – 4 Port RS-232 to USB Converter

ATC-804 is suitable when one USB connection needs to provide multiple RS-232 ports. This is useful in test benches, machine setups, service panels, and applications where multiple serial devices need to be connected to one computer.

Technical points to note:

• Computer interface: USB 2.0 plug and play
• Operating system support: Windows 98 / ME / XP / 2000 / Vista / 7 / 8, Mac and Linux reference
• Field interface: 4-port RS-232
• Transmission rate: 300 bps to 460.8 kbps reference
• Indication LED: sending data red and receiving data green
• Connector: 4-port RS-232 DB9 male
• Power: from USB port or external power supply

Where it is commonly used:

• Multi-device RS-232 test benches
• Serial data acquisition setups
• Machine service stations
• Lab and production testing
• Multi-controller configuration
• Industrial troubleshooting systems

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ATC-830 – TTL to USB Converter

ATC-830 is suitable when a USB computer needs to communicate with TTL logic-level serial devices. This is different from RS-232 and should be selected carefully.

Technical points to note:

• Computer interface: USB 2.0 plug and play
• Operating system support: Windows 98 / ME / XP / 2000 / Vista / 7 / 8, Mac and Linux reference
• Field interface: TTL logic
• Transmission rate: 300 bps to 1 Mbps reference
• Indication LED: sending data red and receiving data green
• Connector: DB9 male connector for TTL with terminal block
• Power: from USB port

Where it is commonly used:

• Embedded board communication
• OEM electronics testing
• Serial debugging
• Development benches
• TTL device configuration
• Microcontroller communication

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Quick Comparison Table

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Key Selection Factors for USB to Serial Converters

1. Confirm the Serial Interface

Start with the field device interface.

• RS-232: ATC-810
• RS-485: ATC-820
• RS-422: ATC-840
• TTL: ATC-830
• Multiple interfaces with isolation: ATC-850
• Multiple RS-232 ports: ATC-804

This is the most important selection step.

2. Check Driver and Operating System Support

USB converters usually need a driver to create a virtual COM port. Confirm support for your laptop operating system before purchase.

For industrial maintenance teams, this matters because many plants still use older laptops and older configuration software.

3. Match Baud Rate and Serial Settings

The converter must support the required baud rate, but the software and connected device must also match:

• Baud rate
• Parity
• Data bits
• Stop bits
• COM port number
• Device address, if Modbus RTU is used

4. Decide Whether Isolation is Needed

Use isolated converters when the communication line is connected to field wiring, different panels, outdoor equipment, or noisy industrial areas.

ATC-850 is the better option when isolation and multi-interface flexibility are required.

5. Confirm Connector Type

Do not assume every DB9 connection is wired the same. Confirm:

• DB9 male / female requirement
• Terminal block availability
• TX/RX pinout
• RS-485 D+ / D- terminals
• TTL voltage level
• Straight or null-modem cable requirement

6. Single Port or Multi-Port Requirement

If only one device is being configured, a single-port converter is enough. If multiple RS-232 devices must be connected together, ATC-804 may be more suitable.

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Common Applications

USB to Serial Converters are commonly used in:

• PLC programming and troubleshooting
• HMI configuration
• VFD setup
• Modbus RTU device testing
• Energy meter communication
• Controller and indicator configuration
• Data logger connection
• Weighing system communication
• Machine diagnostics
• Lab and test bench serial communication
• Embedded system debugging
• Service laptop communication kits

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Common Mistakes to Avoid

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Do This, Not That

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Quick Selection Checklist

Before selecting USB to Serial Converters, confirm:

1. Field interface: RS-232, RS-485, RS-422, or TTL.
2. Number of required serial ports.
3. Required baud rate.
4. Operating system and driver support.
5. COM port compatibility with software.
6. Connector type and pinout.
7. Half-duplex or full-duplex requirement.
8. Isolation requirement.
9. USB power or external power requirement.
10. Final datasheet and wiring diagram before purchase.

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Specifications to Confirm Before Purchase

Final specification should be confirmed from the official datasheet before purchase. For USB to Serial Converters, check:

• USB version
• Supported operating systems
• Driver availability
• Field interface: RS-232 / RS-485 / RS-422 / TTL
• Transmission rate
• Full-duplex or half-duplex operation
• Isolation rating, if applicable
• Connector type
• Terminal block availability
• Power supply method
• LED indication
• Operating temperature
• Cable length
• COM port stability
• Software compatibility
• PLC / HMI / SCADA compatibility
• Modbus RTU compatibility, if required

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Why Buy USB to Serial Converters from Radical TechMart?

At Radical TechMart, the focus is not only to supply a converter, but to help customers select the right communication interface for the actual industrial application.

A buyer may ask for a USB converter, but the real requirement may be:

• USB to RS-232 for old machines
• USB to RS-485 for Modbus RTU networks
• USB to RS-422 for full-duplex serial communication
• USB to TTL for embedded boards
• Isolated USB to serial for noisy plant environments
• Multi-port RS-232 for test benches and service systems

Radical TechMart can support automation engineers, OEMs, panel builders, EPC contractors, maintenance teams, and purchase departments with converter selection, datasheet checking, pricing, availability, and application guidance.

Correct converter selection can reduce commissioning delay, improve troubleshooting speed, and make serial communication more dependable during maintenance work.

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Final Thoughts

USB to Serial Converters should not be selected only by price or connector shape.

The correct model depends on the field interface, operating system, baud rate, driver support, isolation need, connector type, and the actual industrial environment.

For simple RS-232 service work, ATC-810 may be enough. For RS-485 Modbus RTU testing, ATC-820 is more relevant. For RS-422, ATC-840 is suitable. For embedded TTL devices, ATC-830 should be considered. For multiple RS-232 devices, ATC-804 makes sense. For industrial communication where isolation and flexibility matter, ATC-850 is the stronger choice.

In industrial automation, a USB converter is not just a laptop accessory. It is often the bridge between the service engineer and the machine.

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FAQs

1. What is a USB to Serial Converter used for?

A USB to Serial Converter allows a computer or laptop USB port to communicate with serial devices using RS-232, RS-485, RS-422, or TTL communication.

2. Which ATC model is suitable for USB to RS-232 communication?

ATC-810 is suitable for USB to RS-232 communication. ATC-804 is suitable when multiple RS-232 ports are required from one USB connection.

3. Which ATC model is suitable for USB to RS-485 communication?

ATC-820 is suitable for USB to RS-485 communication, especially for Modbus RTU networks, meters, controllers, and field devices.

4. What is the difference between ATC-820 and ATC-850?

ATC-820 is a USB to RS-485 converter. ATC-850 supports RS-232 / RS-422 / RS-485 communication with isolation, making it more suitable for flexible and noisy industrial applications.

5. Can USB to Serial Converters connect with PLC or SCADA?

Yes. They are commonly used for PLC programming, SCADA communication testing, HMI configuration, Modbus RTU diagnostics, and controller setup. Compatibility depends on interface type, driver support, baud rate, and wiring.

6. When should I choose an isolated USB to serial converter?

Choose an isolated converter when communication wiring is connected to field devices, different panels, long cable routes, or noisy industrial areas. Isolation helps reduce ground loop and electrical noise problems.

7. Is TTL the same as RS-232?

No. TTL and RS-232 use different voltage levels. ATC-830 is for TTL logic communication, while ATC-810 is for RS-232 communication.

8. Why is my USB serial converter not communicating?

Common reasons include wrong COM port, missing driver, incorrect baud rate, wrong parity, TX/RX mismatch, RS-485 polarity issue, wrong device address, or selecting the wrong converter type.

Buy ATC products here
A communication converter usually gets attention only when a machine stops talking to the PLC, the SCADA screen stops receiving data, or an old RS-232 device has to be connected to a modern RS-485 network.

That is when the real problem starts.

The purchase team may search for a simple “RS-232 to RS-485 converter,” but the actual requirement may be different. The site may need isolation. The cable distance may be long. The device may need RS-422 instead of RS-485. The network may require a repeater. Or the existing port may not have enough power to run a port-powered device.

This is where RS-232 / RS-422 / RS-485 Interface Converters & Isolators become important.

In industrial automation, serial communication is still used in many PLCs, HMIs, PID controllers, temperature indicators, energy meters, data loggers, weigh indicators, VFDs, CNC machines, and legacy control systems. The right converter helps different devices communicate correctly. The wrong converter creates intermittent data loss, unstable communication, wiring confusion, commissioning delays, and unnecessary troubleshooting.

This guide explains how to select the right ATC serial communication converter or isolator from the following models:

• ATC-101
• ATC-131
• ATC-102
• ATC-155
• ATC-105
• ATC-107N
• ATC-106
• ATC-109N

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What are RS-232 / RS-422 / RS-485 Interface Converters & Isolators?

RS-232, RS-422, and RS-485 are serial communication standards used to transfer data between industrial devices.

In simple words:

RS-232 is commonly used for point-to-point communication over shorter distances. Many old PCs, controllers, instruments, and machines use RS-232.

RS-422 is used when longer-distance differential communication is required, usually with better noise immunity than RS-232.

RS-485 is widely used in industrial automation because it supports long-distance communication and multi-drop networks where multiple devices can communicate on the same bus.

An interface converter changes one signal standard into another. For example, RS-232 to RS-485.

An isolator protects the communication line by electrically separating two sides of the system. This is useful where ground loop, electrical noise, surge, or wiring risk can damage ports or disturb communication.

A line booster or repeater extends communication distance and improves signal strength for long cable runs.

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Why this Matters in Actual Plant Conditions

In actual plant conditions, serial communication problems are rarely obvious.

The PLC may receive data sometimes and fail at other times. The HMI may show values for a few minutes and then freeze. A Modbus device may respond in the panel but fail after installation at site. The communication cable may pass near motors, VFDs, heaters, welding machines, contactors, or high-current lines.

A wrong converter can create:

• No communication between PLC and instrument
• Random Modbus timeout errors
• Data loss over long cable distance
• Damage to RS-232 or RS-485 ports
• Ground loop issues between panels
• Signal noise due to improper isolation
• Wrong wiring between D+ / D- or Tx / Rx terminals
• Commissioning delay because the selected model does not match the application

For purchase managers, all converters may look similar. For an automation engineer, the difference between a basic converter, isolated converter, port-powered isolator, and repeater can decide whether the system works reliably or keeps failing during production.

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How Serial Interface Converters Work

A serial interface converter receives data in one electrical format and retransmits it in another format.

For example, an RS-232 signal from a controller can be converted into RS-485 so that it can communicate with devices located far away or connected in a multi-drop network.

In a typical industrial installation:

1. The RS-232 side connects to a PC, PLC, controller, indicator, or machine port.
2. The converter changes the signal into RS-422 or RS-485.
3. The output side connects to the field communication line.
4. If the converter is isolated, it separates the electrical ground between two sides.
5. If it is a repeater, it boosts or regenerates the signal for longer-distance communication.

This matters because serial communication is not selected only by connector type. You must check communication standard, cable distance, baud rate, isolation requirement, power supply, wiring mode, and number of connected devices.

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Types of RS-232 / RS-422 / RS-485 Interface Converters & Isolators

ATC-101 – RS-232 to RS-422 Interface Converter

ATC-101 is suitable when an RS-232 device needs to communicate with an RS-422 line. This type of converter is useful when the original device has only an RS-232 port but the application requires longer cable distance or differential communication through RS-422.

Technical points to note:

• Function: RS-232 to RS-422 interface conversion
• Interface reference: EIA RS-232C and RS-422 standard
• Connector: RS-232 DB9 female, RS-422 DB9 male / terminal block reference
• Operation mode: asynchronous half duplex
• Data rate: 300 bps to 115.2 kbps reference
• Distance: up to 4000 ft reference
• Power: port powered from RS-232 DTR / TD reference
• Certifications visible: RoHS, CE, FCC

Where it is commonly used:

• RS-232 controller to RS-422 field device connection
• Old machine communication extension
• Industrial controller data link
• Panel-to-equipment serial communication
• Factory automation communication retrofit
• Serial device integration in control rooms

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ATC-131 – RS-232 Port Powered Isolator

ATC-131 is suitable when an RS-232 communication line needs electrical isolation. This is useful where the connected devices are installed in different panels, different grounding conditions, or electrically noisy areas.

Technical points to note:

• Function: RS-232 port-powered isolator
• Interface reference: EIA RS-232C standard
• Connector reference: RS-232 DB9 female / DB25 male
• Operation mode: asynchronous full duplex
• Distance reference: up to 300 m at lower data rate conditions
• Isolation reference: 2500 V in succession or 7500 V pulse
• Power: port powered from RS-232 DTR / TD reference
• Operating environment reference: -20°C to 70°C, 5% to 95% RH

Where it is commonly used:

• PLC programming ports
• PC to controller communication
• RS-232 data acquisition connections
• Machine tool communication
• Electrically noisy industrial panels
• Protection of older RS-232 devices

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ATC-102 – RS-232 to TTL Port Powered Converter

ATC-102 is suitable when an RS-232 serial port needs to communicate with TTL-level serial electronics. This is more common in embedded devices, custom control boards, testing setups, and electronic interface applications.

Technical points to note:

• Function: RS-232 to TTL conversion
• Interface reference: EIA RS-232C and TTL standard
• Connector reference: RS-232 DB9 female, TTL DB9 male / terminal block
• Operation mode: asynchronous communication
• Data rate reference: 300 bps to 115.2 kbps
• TTL-side distance reference: short-distance TTL communication
• Power: port powered from RS-232 DTR / TD reference
• Certifications visible: RoHS, CE, FCC

Where it is commonly used:

• Embedded controller communication
• Testing and development benches
• RS-232 to TTL signal conversion
• Custom machine electronics
• Serial communication troubleshooting
• OEM control board integration

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ATC-155 – RS-232 Isolator Line Booster

ATC-155 is useful when an RS-232 communication line needs both isolation and distance extension. This is suitable when the RS-232 connection is longer than normal practical limits or is exposed to industrial noise.

Technical points to note:

• Function: RS-232 isolator line booster
• Interface reference: EIA RS-232C and CCITT V.24
• Connector reference: RS-232 DB9 / DB25 DCE style connection
• Operation mode: asynchronous full duplex / simplex reference
• Distance reference: suitable for extended RS-232 communication
• Isolation reference: 3500 V or 7500 V impulse reference
• Power: serial port powered supply
• Feature: photoelectric isolation to help prevent device damage

Where it is commonly used:

• Long RS-232 communication runs
• PC to machine communication
• Industrial weighing systems
• Remote controller communication
• Legacy equipment communication extension
• Noisy electrical panel environments

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ATC-105 – RS-232 to RS-422/485 Isolated Converter

ATC-105 is suitable when an RS-232 device needs to connect to RS-422 or RS-485 communication with isolation. This is useful in industrial panels where noise, ground loop, and device protection matter.

Technical points to note:

• Function: isolated RS-232 to RS-422/485 conversion
• Interface reference: EIA RS-232C and RS-485/422 standard
• Connector reference: RS-232 DB9 female, RS-485/422 terminal block
• Operation mode: asynchronous half or full duplex reference
• Data rate reference: up to 115.2 kbps range shown
• Transmission distance reference: long-distance serial communication
• Power reference: external DC power
• Isolation: built-in photoelectric isolation above 3500 V reference

Where it is commonly used:

• PLC to RS-485 field instrument communication
• SCADA serial network integration
• Modbus RTU communication lines
• Long-distance machine communication
• Panel-to-field device communication
• Noisy industrial environments

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ATC-107N – RS-232 to RS-422/485 Interface Converter

ATC-107N is suitable when a wall-mounted industrial converter is required for RS-232 to RS-422/485 communication. It is useful in control panels, cabinets, and machine interfaces where converter mounting and wiring access matter.

Technical points to note:

• Function: RS-232 to RS-422/485 interface conversion
• Product style: industrial-class wall-mounted interface converter
• Interface reference: EIA RS-232C and RS-485/422 standard
• Connector reference: RS-232 RJ45 with DB9 cable / RS-485/422 terminal
• Operation mode: asynchronous half/full duplex reference
• Data rate reference: 300 bps to 115.2 kbps
• Isolation reference: 3500 VRMS / 500 VDC sequence reference
• Protection: photoelectric isolation to help prevent device damage

Where it is commonly used:

• Control panel serial communication
• PLC and HMI communication retrofit
• RS-485 field device networking
• Industrial automation cabinets
• OEM machine communication
• SCADA or data acquisition systems

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ATC-106 – RS-232 to RS-485 Interface Converter

ATC-106 is suitable when a simple RS-232 device needs to communicate with an RS-485 network. This is one of the most common requirements in industrial automation, especially for Modbus RTU communication.

Technical points to note:

• Function: RS-232 to RS-485 interface conversion
• Interface reference: EIA RS-232C and RS-485 standard
• Connector reference: RS-232 DB9 female, RS-485 DB9 male / terminal block
• Operation mode: asynchronous half duplex
• Data rate reference: 300 bps to 115.2 kbps
• Distance reference: up to 4000 ft
• Power: port powered from RS-232 DTR / TD reference
• Load capacity reference: maximum 32 nodes

Where it is commonly used:

• Modbus RTU communication
• Energy meter communication
• Controller to RS-485 device connection
• HMI / PLC serial interface
• Data logger communication
• Industrial instrument networking

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ATC-109N – RS-422/485 Isolated Data Repeater

ATC-109N is suitable when an RS-422 or RS-485 network needs signal regeneration, isolation, or distance extension. It is useful in larger plants where one communication line has to cover long cable routes or multiple device zones.

Technical points to note:

• Function: RS-422/485 isolated data repeater
• Product style: industrial-class wall-mounted interface converter / repeater
• Interface reference: EIA RS-485/422 standard
• Connector reference: terminal block connection
• Operation mode: asynchronous half/full duplex reference
• Distance reference: long-distance RS-485/422 extension
• Isolation reference: 3500 VRMS / 500 VDC sequence reference
• Protection: photoelectric isolation to prevent device damage

Where it is commonly used:

• Large RS-485 Modbus RTU networks
• Long cable runs between plant sections
• Multi-panel communication systems
• SCADA field communication lines
• Factory automation networks
• RS-485 network segmentation

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Key Selection Factors for RS-232 / RS-422 / RS-485 Converters & Isolators

1. Communication Standard

First confirm what your existing device has and what the target network requires.

• RS-232 to RS-422: consider ATC-101
• RS-232 isolation only: consider ATC-131
• RS-232 to TTL: consider ATC-102
• RS-232 line isolation/boosting: consider ATC-155
• RS-232 to isolated RS-422/485: consider ATC-105 or ATC-107N
• RS-232 to RS-485 basic conversion: consider ATC-106
• RS-422/485 network extension: consider ATC-109N

Do not select only by connector appearance. RS-232, TTL, RS-422, and RS-485 are electrically different.

2. Isolation Requirement

Isolation becomes important when communication runs between panels, different power sources, outdoor devices, or electrically noisy areas.

Choose an isolated converter when:

• Communication cable is long
• Devices are in different panels
• Ground loop is suspected
• VFDs, motors, heaters, or contactors are nearby
• RS-232 / RS-485 ports have failed earlier
• Stable communication is critical

3. Distance

RS-232 is usually better for short point-to-point communication. RS-485 and RS-422 are better for longer distances.

If distance is the main issue, check:

• Cable length
• Baud rate
• Cable quality
• Shielding
• Termination resistor
• Repeater requirement
• Electrical noise

For long RS-485 networks, ATC-109N may be more suitable than a simple converter.

4. Baud Rate

The PDF product cards mention common serial data rate ranges such as 300 bps to 115.2 kbps for several models. Before purchase, confirm the baud rate of your PLC, controller, meter, or instrument.

A mismatch in baud rate, parity, stop bit, or data bit can make a correct converter look faulty.

5. Power Supply

Some models are port powered, while others may require external DC power.

Port-powered models are convenient, but not every RS-232 port can supply enough power. For industrial installations, external power models may be more stable.

6. Wiring Mode

RS-485 can be 2-wire half-duplex or 4-wire full-duplex depending on the device and protocol. RS-422 usually uses differential transmit and receive lines.

Before ordering, confirm:

• 2-wire or 4-wire communication
• Half duplex or full duplex
• Terminal names
• D+ / D- polarity
• Tx+ / Tx- and Rx+ / Rx- wiring
• Shield and grounding method

7. Connector Type

The visible product cards show combinations of DB9, DB25, RJ45, and terminal block connections depending on the model. Confirm connector type before purchase because site installation delays often happen due to connector mismatch.

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Common Applications

RS-232 / RS-422 / RS-485 Interface Converters & Isolators are commonly used in:

• PLC to field device communication
• HMI to controller communication
• SCADA data acquisition
• Modbus RTU networks
• Energy meter communication
• Temperature controller communication
• Data logger connection
• Weighing scale and weigh indicator communication
• VFD communication
• CNC and machine tool communication
• Factory automation retrofits
• Panel builder communication interfaces
• OEM machine serial ports
• Legacy equipment integration

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Common Mistakes to Avoid

---

Do This, Not That

---

Quick Selection Checklist

Before selecting RS-232 / RS-422 / RS-485 Interface Converters & Isolators, confirm:

1. Existing device interface: RS-232, RS-422, RS-485, or TTL.
2. Target communication interface.
3. Cable distance between devices.
4. Required baud rate and serial settings.
5. Half-duplex or full-duplex operation.
6. 2-wire or 4-wire RS-485 requirement.
7. Isolation requirement.
8. Power supply method: port powered or external power.
9. Connector type: DB9, DB25, RJ45, or terminal block.
10. Number of devices on the network.
11. Noise level near cable routing.
12. PLC, HMI, SCADA, meter, or controller compatibility.
13. Datasheet and wiring diagram before final purchase.

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Specifications to Confirm Before Purchase

Final specification should be confirmed from the official datasheet before purchase. For serial converters and isolators, check:

• Input interface
• Output interface
• Supported standard: RS-232 / RS-422 / RS-485 / TTL
• Connector type
• Baud rate range
• Maximum communication distance
• Half-duplex / full-duplex support
• Isolation rating
• Surge or ESD protection, if required
• Power supply method
• Operating temperature
• Humidity range
• Mounting style
• Supported node count for RS-485
• Terminal wiring diagram
• Compatibility with PLC, HMI, SCADA, PC, controller, or field instrument
• Certifications or compliance requirements

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Why Buy RS-232 / RS-422 / RS-485 Converters & Isolators from Radical TechMart?

At Radical TechMart, the focus is not only to supply a converter, but to help customers select the right communication solution for the actual industrial application.

A buyer may ask for an RS-232 to RS-485 converter, but the real requirement may be:

• Basic RS-232 to RS-485 conversion
• Isolated RS-232 to RS-485 conversion
• RS-232 to RS-422 communication
• RS-232 line isolation
• TTL-level serial conversion
• RS-485 network extension
• Long-distance communication support
• PLC / SCADA / HMI serial communication integration

Radical TechMart can support buyers with product selection for automation panels, legacy machine communication, Modbus RTU networks, instrument integration, data logging systems, and industrial communication troubleshooting.

For OEMs, panel builders, EPC contractors, factories, and maintenance teams, correct converter selection can reduce commissioning time, prevent port damage, and improve communication reliability.

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Final Thoughts

RS-232 / RS-422 / RS-485 Interface Converters & Isolators should not be selected only by model number or price.

The right selection depends on the communication standard, distance, isolation requirement, baud rate, connector type, wiring mode, and industrial environment.

For a short RS-232 to RS-485 requirement, a basic converter may be enough. For noisy plants, long cable runs, or different panel grounding, isolated converters and repeaters become important. For legacy systems, the correct converter can keep old machines communicating with modern PLC, SCADA, or data logging systems.

In industrial applications, communication reliability is not achieved by buying any converter. It is achieved by matching the converter to the signal, wiring, environment, and control-system requirement.

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FAQs

1. What is the use of an RS-232 to RS-485 converter?

An RS-232 to RS-485 converter allows an RS-232 device to communicate with an RS-485 network. It is commonly used for PLCs, HMIs, meters, controllers, data loggers, and Modbus RTU devices.

2. When should I use an isolated RS-485 converter?

Use an isolated converter when the communication line is long, electrically noisy, connected between different panels, or exposed to ground loop risk. Isolation helps protect communication ports and improves signal stability.

3. What is the difference between ATC-106 and ATC-105?

ATC-106 is suitable for basic RS-232 to RS-485 conversion. ATC-105 is better suited when RS-232 to RS-422/485 conversion is required with isolation. Final selection should be based on wiring distance, noise level, isolation need, and communication mode.

4. What is the use of ATC-109N?

ATC-109N is used as an RS-422/485 isolated data repeater. It helps extend RS-485 or RS-422 communication distance and isolate network sections in industrial communication systems.

5. Can these converters connect with PLC or SCADA?

Yes, these converters are commonly used in PLC, SCADA, HMI, controller, meter, and data acquisition systems. Compatibility depends on the required interface, protocol, baud rate, wiring mode, and serial settings.

6. What should I check before buying an RS-485 converter?

Check input/output interface, baud rate, distance, half-duplex or full-duplex requirement, isolation, connector type, power supply, RS-485 node count, and compatibility with your PLC, HMI, SCADA, or instrument.

7. Do I need a repeater for every RS-485 network?

No. A repeater is needed when the network distance is long, device count is high, signal quality is poor, or the network needs isolation between sections. For small networks, a repeater may not be required.

8. Are port-powered converters suitable for all applications?

Port-powered converters are convenient, but they depend on the host RS-232 port. Before selecting a port-powered model, confirm that the connected device can provide enough power through the RS-232 signal lines.