9 Aug
2010
9 Aug
'10
1:24 p.m.
snip snip snip
I checked with a co-worker (who did service PDP-11's)
He thinks it may have been used as X.25 router/ lineinterface.
Usually there is also a M3112 card (boot/terminator for DECSA)
I _knew_ I recognised thase numbers...
You are essentially right. They are essentially a custom 'processor' for
X25 and other protocols used in the DECSA (Digital Ethernet
Communications Server Aparatus or something similar).
A DECSA is a special cabinet containing a PDP11/24 CPU, a boot/terminator
board, those 2 protocol cards, RAM, a DEUNA (ethernet interface) and one
or more line cards (dual height, in special slots). It's a sort of
terminal server/X25 interface/etc
I have one, and it led me to propose 'ARD's law of DECSA construction'
which states 'The lower the importnace of a part of a DECSA, the more
screws hold it in place'. This is illustrated by
The logic boards plu in with no screws
The PSU(s) are held in by 2 screws (each, if you hve 2 PSUs)
The fan tray is held in by 4 screws (this is less important than the
above, the thing will run for a short time with no fan tray).
But the metal grille over the fan tray is held on by an amazing 28 screws
(I had to take them all out and put them all back to remvoe the fan tray
before removing the backplane...
-tony
"M3110 DRCSA U Protocol assist #1
w/special character check
and CRC (DEC/DLC/DRCSA)"
"M3111 DRCSA U Protocol assist #2 w/special character check
and CRC (DEC/DLC/DRCSA)"
No clear idea about those two...