PDP-11/44 mystery card

Hi I've acquired two PDP-11/44 and have just now gone throught the list of cards in the cpu-boxes and the spares. Here is a list: http://www.update.uu.se/~pontus/slask/11-44-kort.txt Nothing special, I've used the field guide to identify most cards. I've only marked one card of each kind. There is two cards connected with ribbon cables that I can't identify. They are made by Data Management Labs in San Jose and are labled DML 750 Board A and Board B. There are some numbers as well (in no particular order) 980-8043 710-1921-001 There are some bitslice chips and a whole bunch of roms. Anything that rings a bell with anyone? Also I wonder what the "M7251 KG11-A U Network interface XOR and CRC block check option" "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)" are used for? Cheers, Pontus