tty usually means a serial port device file in AIX, like Zaxxon said, you normally can found something like /dev/tty0 or /dev/tty1. A tty device can be config as a rs-232 port, rs-485 port, or asyn...
Actually, AIX is a free item when you buy a IBM machine, it's not sold separately. Anyone know eConfig tool from IBM can make such config list to find out.
For servers before/include F50 and Workstation before/include 43p-150, are ivory in color. later are black. for some machine with 4.2, I suspect it's a F30/F40 or 140 or before.