Dec DMX11--What was it?

[Chris Zach via cctalk]

Anyone know about the Dec DMX11? It was apparently a 64 serial line Mux 
that plugged into pdp11 Unibus systems and had a fair amount of both 
intelligence and insanity on board. Reason is I'm looking into some old 
documentation about late 1970's Tote systems for Asian race tracks and 
the system they were building was beyond astronomical in terms of insanity.

(As in an 8 way pdp11/70 system cluster, with 11/04's running these 
DMX11's to hundreds of terminals)