Doepfer

i'm putting together a new rack to keep steady company with my A100 
Basic...i've got a Doepfer PS2, bus rail (and a BBD 2048 hehe)....i'm 
doing some window shopping and like the sound of the Analogue Systems 
RS Putney filter and the features of other mods seem to compliment the 
Doepfer nicely (don't worry Mr. Doepfer, i still love you)...so what 
does it take to hook up the AS stuff to the doepfer PS2/bus rail? i 
heard something about  a special plug or something...