Prevent Socat from closing

[Paolo84]

Good afternoon,
As total linux newbie I'm reading this forum since few weeks and it helped me to solve most of the problems i found on my way.
Unfortunately, now i have to ask for help.
I'm working on Raspberry Pi with ArchLinux Arm.

The purpose of my project is to run RPi as Access Point with DHCP server and providing to the connected clients a Serial / TCP pipe to dialogue with a machine plugged to the RPi.

My project perfectly works thanks to Socat, which i start this way:
socat PIPE:/dev/ttyACM0 TCP-LISTEN:9100

Problems start when the client, after connecting to the RPi though port 9100, closes the connection. Socat (as it has to do, i guess) goes EOF and terminate.
How can i configure it to keep the pipe opened for further connection from the same/other clients?
Furthermore: i'm now starting socat thought systemd on startup: is this the right way to open the pipe on boot?
Thank you very much in advance for your help.