I left in 79, I designed the AUtodin II mode 1A//Mode VI line usints.
Those were synchronous comms interfaces for Bisync.ADCCP/ etc
connections while CSS did the Mode 1 I think it was Asynch interface
line unit.
I suspect DMX is the commercial version of that Autodin II Asynch
design, using the KMX/COMMIOP cpu and a dedicated unibus system unit
set to support the lineunits
BUT I could be wrong maybe DMX was something completely different but
it seems to tickle my memory.
bb