PC-Interface mc-18/20 Kpl.-Se Graupner 4181.2 Required for communication (copying, storing) between transmitters mc-18 (type 90)* and mc-20 and personal-computer, resp. (IBM compatible). An interface distributor (No. 4181.3) for plug connection at the transmitter is furnished with the programming interface. * When installing the distributor into earlier mc-18 transmitter, the left sidepart of the transmitter has to be replaced by No. 4810.22