SLC ignores VT100 terminal on serial port after reboot?

[Len Schwer]

I have a VT100 termninal (actually a Mac SE running VersaTerm Pro
emulation of a VT100). I have managed to use the terminal emulation often
over the past 4 months I've had the SLC. The problem occurs when I need to
reboot the SLC for various reasons.

Upon reboot, the SLC won't recognize the VT100 hanging on the serial port.
I am using Sun's split A/B cable with the B side and a null modem in the
line. I have solved this problem twice  by just plugging and unplugging
connectors and null modemes and A/B cables until I for some random reason
the SLC is suddenly happy. What I don't understand is I didn't change any
connections between using the VT100 (I actually used the VT100 to halt the
system because the screen lock wouldn't unlock) and the reboot.

The only clues I have are when I change the parity of the VT100 emulation,
the console on the SLC reports: "vmunix" zs1: parity error ignored" I have
check the /ect/termcap file and VT100 is still there, /etc/ttytab has both
the A and B ports turned on at 9600, and I've issue a zillion "kill -HUP
1".

Anyone got any suggestions?   Thanks,  --Len Schwer  schwer at unix.sri.com