There is a program called cu "Connect UNIX" it is in IRIX .. you need to install eoe.sw.uucp or something like that ... look for uucp in your IRIX sets as it is not installed by default... I have a FreeBSD laptop which I use cu to connect to various serial ports. I think the command syntax is something like ....
cu -l /dev/ttys0 -s 384000
Extract from man page
CU(1C) NAME cu - call another UNIX system SYNOPSIS cu [options] [-s speed] -l line cu [options] [-s speed] [-l line] [-n] telno cu [options] systemname where options can be any of: [-h] [-d] [-o | -e] [-c class]
Octanes can do 38.4kbps. Make sure that /etc/uucp/Devices and /etc/uucp/Systems on the Octane are properly configured.