[comp.dcom.telecom] AT&T Phone Model 7405

MJK2660@RITVM.BITNET (Mike Koziol) (11/01/87)

This past year we had an AT&T system 85 switch installed on campus and
an AT&T model 7405 (with display panel) telephone was installed in my
office. I was told at the outside that the phone was capable of many
options, and to never unplug it as it may not work when I plugged it in
again. Since I'm basically a curious sort a friend and my self recently
disassembled it and found two rather large circuit boards populated
nicely with lots of chips and a couple of EPROMS. I have a few questions:
what "processing" does this phone do, what is stored in memory, how
volatile is the memory, what is the phone capable of, and finally why
shouldn't I unplug it? Any ideas?