The comservd program provides a facility to access network terminal
server serial ports, such as those available on Xyplex terminal server
models, via /dev device file entries.  This allows programs such as
tip(1) to access devices connected to the terminal server serial
ports.

Additionally, comservd can serve up local serial ports to remote
systems, effectively turning the system running comservd into a
terminal server with respect to its own local serial ports.

WWW: http://www.bsdhome.com/comserv/