Here is a free program to convert TCP/UDP packets to RS232 serial port:
http://www.sailsoft.nl/ipanema.htm
Could this do the job for you?

"Victor Fraenckel" schreef in bericht
...
Larry wrote:
Hi,
I'm trying to connect a PC with Nav software to the I/O interface on a
furuno f100 (pc/lan serial output). The connection is a 9 pin serial
to a standard lan cable connection (rj45). How do I set up the PC/LAN
to accept the signal?
Thanks


Maybe this can get'r done for around 30USD:

http://www.siteplayer.com/telnet/index.html

HTH

Vic