Use TCP Client mode when the remote device listens
Choose TCP Client mode when a PLC, meter, serial device server, gateway, or TCP endpoint already listens on an IP address and port. The bridge connects out to that endpoint and presents a local virtual COM port to Windows software.
Use TCP Server mode when the Windows machine owns the serial port
Choose TCP Server mode when a real serial device is attached to the Windows machine and another system should connect over TCP. The bridge listens on a TCP port and forwards traffic to the local serial port.
Simple decision rule
- If Windows software needs a local COM port for a remote TCP device, use TCP Client mode.
- If a remote TCP client needs access to a real COM port on this Windows machine, use TCP Server mode.
- If serial settings must be negotiated over the network, consider RFC2217 where supported.
Common mistakes
Do not configure both sides to listen. Do not configure both sides to connect out. One side must be the server, and one side must be the client.