Components: GmM USB RS485 Converter

Mon, 01 Jan 0001 00:00:00 +0000

These informations are provided “AS IS” and without any warranty of any kind.

This module provides an 1 Channel USB to RS485 Converter.

It’s one of the most common designs, sold under various different brands.

It is very convenient to use, and works quite well despite being based on a fake FT232RL chip. Seems to run reliable up to 115200 bps. But the bias and termination resistors can’t get disabled (unless removed completely), so there should only be one of those modules on any bus, either at the beginning or the end.

That being said, those modules communicate well with various RS485 and Modbus RTU based devices like power meters or solar inverters. Some use cases might require the use of an additional USB isolator though, as there is none build-in.

The 4 jumpers in the middle of the board bridge GND, TX, RX and +5V from the USB-Serial side to the RS485 one. By removing those, and connecting to the pins directly, the module can work either as a pure USB ↔ TTL serial converter, or a TTL ↔ RS485 converter.

Pros

PCB and components seem to be good quality, works flawlessly
USB Type B Socket, Plug-in Screw Terminals and its compact board design make it a perfect choice for DIN Rail mounting
Very decent price-performance ratio

Cons

FAKE FT232RL chip (Serial A50285BI)
Not possible to disable the 120 Ω termination or the 4.7 KΩ A&B bias resistors

General Overview / Specs


Model	GmM ???
Manufacturer	???
Made in	???
Power Supply Voltage	5 V (USB)
Max. USB Current	???
USB Connector	USB 2.0 Type B Socket
USB Serial Vendor	`0403` Future Technology Devices International, Ltd
USB Serial Product	`6001` FT232 Serial (UART) IC
Max. communication speed	921600 bps ???
RS485 Connector	Plug-in Screw Terminal 5.08 mm (A/B/G)
Protections	TVS
LED Indicators	Power, RX, TX
Dimensions	53.5 × 18.37
Operating Temperature	???

Further Information

Availability / Order

AliExpress

Case / Mounting / DIN-Rail

3D Printed Case

I’ve designed a DIN-Rail mountable case for this board, it will soon be available on eBay.de

As most of my cases for electronic devices, it has been printed using insulating and flame-retardant (UL 94 HB) DuraPro ABS filament from Extrudr.

STL Files for 3D Printing

The .stl files for the DIN-Rail case are available on Cults3D.com

Components: MCS-83F USB RS485 Converter

Mon, 01 Jan 0001 00:00:00 +0000

These informations are provided “AS IS” and without any warranty of any kind.

This module provides an 1 Channel USB to RS485 Converter.

It is very convenient to use, and works quite well despite being based on a fake FT232RL chip. Seems to run reliable up to 115200 bps.

That being said, those modules communicate well with various RS485 and Modbus RTU based devices like power meters or solar inverters.

Pros

PCB and components seem to be good quality, works flawlessly
USB Type B Socket, Plug-in Screw Terminals and its compact board design make it a perfect choice for DIN Rail mounting
Decent price-performance ratio

Cons

FAKE FT232RL chip (Serial A50285BI)

General Overview / Specs


Model	MCS-83F
Manufacturer	Mercury Technologies HK / SerialTek
Made in	Hong Kong
Power Supply Voltage	5 V (USB)
Max. USB Current	???
USB Connector	USB 2.0 Type B Socket
USB Serial Vendor	`0403` Future Technology Devices International, Ltd
USB Serial Product	`6001` FT232 Serial (UART) IC
Max. communication speed	921600 bps ???
RS485 Connector	Plug-in Screw Terminal 5.08 mm (A/B/G)
Protections	TVS
LED Indicators	Power, RX, TX
Dimensions	??? × ???
Operating Temperature	???

j3w5.de – USB ↔ RS485 Serial Converter

Components: GmM USB RS485 Converter

Pros

Cons

General Overview / Specs

Further Information

Availability / Order

AliExpress

Case / Mounting / DIN-Rail

3D Printed Case

STL Files for 3D Printing

Components: MCS-83F USB RS485 Converter

Pros

Cons

General Overview / Specs

Availability / Order

AliExpress