Socat Parameters - Share USB RS485 Adapter over Network

[mojonba]

Hi, I am interested in running nodejs-Poolcontroller in an rPi5 that is considerably farther from the pool pump and would like to try an rPi Zero 2W with an USB RS485 adapter right next to the "share" its RS485 adapter through the network using Socat. I have tried countless commandlines options that I have found through the web, however the remote serial connection opens, but immediately closes. Can anyone please help troubleshoot.

 socat -d -d -d tcp-listen:4141,reuseaddr,fork file:/dev/ttyUSB0,nonblock,cs8,b9600,cstopb=0,raw,echo=0


2025/09/21 06:54:54 socat[1120] N socket 1 (fd 6) is at EOF
2025/09/21 06:54:54 socat[832] I accept(5, {2, AF=2 192.168.105.5:56808}, 16) -> 6
2025/09/21 06:54:54 socat[832] N accepting connection from AF=2 192.168.105.5:56808 on AF=2 192.168.105.40:4141
2025/09/21 06:54:54 socat[832] I permitting connection from AF=2 192.168.105.5:56808
2025/09/21 06:54:54 socat[832] N forked off child process 1121
2025/09/21 06:54:54 socat[832] I close(6)
2025/09/21 06:54:54 socat[832] I still listening
2025/09/21 06:54:54 socat[832] N listening on AF=2 0.0.0.0:4141
2025/09/21 06:54:54 socat[1121] I just born: child process 1121
2025/09/21 06:54:54 socat[1121] I close(4)
2025/09/21 06:54:54 socat[1121] I close(3)
2025/09/21 06:54:54 socat[1121] I just born: child process 1121
2025/09/21 06:54:54 socat[1121] I close(5)
2025/09/21 06:54:54 socat[1121] I setting option "o-nonblock" to 1
2025/09/21 06:54:54 socat[1121] I setting option "cs8"
2025/09/21 06:54:54 socat[1121] I setting option "b9600"
2025/09/21 06:54:54 socat[1121] I setting option "cstopb" to 0
2025/09/21 06:54:54 socat[1121] I setting option "raw"
2025/09/21 06:54:54 socat[1121] I setting option "echo" to 0
2025/09/21 06:54:54 socat[1121] N opening character device "/dev/ttyUSB0" for reading and writing
2025/09/21 06:54:54 socat[1121] I open("/dev/ttyUSB0", 04002, 0666) -> 5
2025/09/21 06:54:54 socat[1121] I resolved and opened all sock addresses
2025/09/21 06:54:54 socat[1121] N starting data transfer loop with FDs [6,6] and [5,5]
2025/09/21 06:54:55 socat[1120] I poll timed out (no data within 0.500000 seconds)
2025/09/21 06:54:55 socat[1120] I shutdown(6, 2)
2025/09/21 06:54:55 socat[1120] N exiting with status 0
2025/09/21 06:54:55 socat[832] N childdied(): handling signal 17
2025/09/21 06:54:55 socat[832] I childdied(signum=17)
2025/09/21 06:54:55 socat[832] I childdied(17): cannot identify child 1120
2025/09/21 06:54:55 socat[832] I waitpid(): child 1120 exited with status 0
2025/09/21 06:54:55 socat[832] I waitpid(-1, {}, WNOHANG): no child has exited
2025/09/21 06:54:55 socat[832] I childdied() finished

[9/21/2025, 6:50:20 AM] warn: Net connect (socat) connection idle: 192.168.105.40:4141 retrying connection.
[9/21/2025, 6:50:20 AM] info: Net connect (socat) 1 request close: 192.168.105.40:4141
[9/21/2025, 6:50:20 AM] info: Net connect (socat) 1 sent FIN packet: 192.168.105.40:4141
[9/21/2025, 6:50:20 AM] info: Net connect (socat) destroy socket: 192.168.105.40:4141
[9/21/2025, 6:50:20 AM] info: Net connect (socat) 1 successfully closed: 192.168.105.40:4141
[9/21/2025, 6:50:20 AM] info: Net connect (socat) 1 connected to: 192.168.105.40:4141
[9/21/2025, 6:50:20 AM] info: Net connect (socat) Connection 1 connected
[9/21/2025, 6:50:20 AM] info: Net connect (socat) 1 ready and communicating: 192.168.105.40:4141

[tagyoureit]

See https://github.com/tagyoureit/nodejs-poolController/wiki/Socat.