When my Windows XP is runnning, it recognizes the COM1 and is able to communicate. The byte-streams are actually piped to /tmp/com1_sock (if we don't do anything, it just acts as a dummy). If we want to forward it as a listening port (e.g, as a tcp server so remote systems are able to communicate with the COM1 via TCP/IP), on Linux host's shell type: socat UNIX-CONNECT:/tmp/com1_socket TCP-LISTEN:
Here's the example:
socat UNIX-CONNECT:/tmp/com1_socket TCP-LISTEN:8040
From another terminal (either local machine or remote machine) we can telnet to this port. For example, from our own Linux host, we can communicate to the Hyperterminal running under Windows-XP guest via this virtual serial port by telnetting to the port:
Voila! Our Linux machine will display anything we type on Hyperminal. This opens up a lot of experiments for us.