Create a virtual serial port connection over TCP

Question

I am developing an application that should be able to write to a virtual serial port and receive data through the same port from remote clients over network.

The application runs on a linux server. I am new in using serial ports and I have some questions on this topic.

Clients

The client can establish a TCP connection to a server. When we setup a client, we have to provide the IP address of the server, a tcp port (usually 8080) and a virtual com port.

The client then will automatically try to connect to the server.

Server

The server has a virtual com port, the same we set in the client config (e.g. COM1). When an application on the server writes data to this port, the data should be send to all clients connected via tcp. The response from the clients is send over TCP back to the server which can read it over the virtual serial port.

Question

On windows I used a virtual serial port connector http://www.eterlogic.com/Products.VSPE.html which did most of the work. However I want to solve this problem on linux machines.

My question is, how can I create a TCP server that has a virtual serial port attached and can send/receive data through this port over TCP to listening clients?

yegorich · Accepted Answer · 2014-03-27 15:42:25Z

50

Try socat. Possible scenario:

socat pty,link=/dev/virtualcom0,raw tcp:192.168.254.254:8080&

socat creates TCP connection to 192.168.254.254:8080, so that everything, that will be written to /dev/virtualcom0 will be forwarded to 192.168.254.254:8080 and vice versa.

Another approach would be to use RFC2217 via ser2net on Linux sever side and RFC2217 driver on Windows side (for example http://www.hw-group.com/products/hw_vsp/index_en.html single port version). You can also try to get http://pyserial.sourceforge.net/ to work with ser2net.

edited Mar 27, 2014 at 15:42

answered Mar 27, 2014 at 13:30

yegorich

4,8793 gold badges34 silver badges40 bronze badges

Sign up to request clarification or add additional context in comments.

9 Comments

DarkLeafyGreen Over a year ago

Thanks, does this create the virtual com port? I think this just links an existing one to the tcp server. However, I already did what you say here superuser.com/questions/733552/… my problem is that I cannot write to the com port.

yegorich Over a year ago

socat would create /dev/virtualcom0, so this is a virtual port. I'm using socat with a VScom NET-CAN 110 device and it is working like a charm. The instructions are here.

DarkLeafyGreen Over a year ago

and can you say what virtualcom0 would be on windows? If I want to connect from windows client to linux that has virtualcom0 port, what should I select on windwos, COM1, COM2...?

m4rlord Over a year ago

How do i disconnect this bridge?

yegorich Over a year ago

@multiplayer1080 try killall socat

|

Martin Valgur · Accepted Answer · 2022-08-30 07:40:16Z

you have socat and ser2net and other programs but my experience is very bad... not working properly. I've done this small python program, can be useful. Update port, baudrate... then use any tcp client. Remove first line if don't want to use is as auto executable script

#!/usr/bin/python import socket import sys import serial #open serial port ser = serial.Serial('/dev/ttyAMA0', 115200, timeout=0) #create socket sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM) sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1) sock.setsockopt(socket.SOL_SOCKET, socket.SO_KEEPALIVE, 1) #bond to the port. Don't use localhost to accept external connections server_address = ('', 2105) print('starting up on {} port {}'.format(*server_address)) sock.bind(server_address) #listen sock.listen(1) #loop while True: #waits for a new connection print('waiting for a connection') connection, client_address = sock.accept() try: print('connection from', client_address) #continously send from serial port to tcp and viceversa connection.settimeout(0.1) while True: try: data = connection.recv(16) if data == '': break ser.write(data) except KeyboardInterrupt: connection.close() sys.exit() except Exception as e: pass received_data = ser.read(ser.inWaiting()) connection.sendall(received_data) except Exception as e: print e finally: #clean up connection connection.close()

Jenny Bredst · Accepted Answer · 2017-08-08 08:47:33Z

The software will help to establish server and client connection over TCP http://www.serial-com-port.com/

I use it for creating virtual serial communications over network, but I have the real RS232 port on the computer. So I just transfer the data over network. If you need to create a virtual COM on the server too, use the Virtual Serial Port Driver.

Note: this is not free software, and has only a 14-day trial period, as of the time of my comment.

R.Lang · Accepted Answer · 2024-12-12 08:56:20Z

I use Serial to Ethernet Connector by Electronic Team for this. I’m on Windows but the site says there’s a Linux version available too.

Collectives™ on Stack Overflow

Create a virtual serial port connection over TCP

4 Answers 4

9 Comments

Comments

1 Comment

Comments

Hot Network Questions

Collectives™ on Stack Overflow

4 Answers 4

9 Comments

Comments

1 Comment

Comments

Related