Source assignment panel. Provides a convenient means of assigning any one of 12 intercom channels and/or three program audio channels to 26 individual or groups of intercom user stations. Viewed as a matrix switch, it transforms a basic two buss intercom system into a 15-bus system. When used as an intermediary between Series 800 (conference line) master stations and TW intercom system user stations, the SAP-1626 distributes the master station channels to each group of user stations. While the master stations have multiple channel capability and can access a number of lines independently or simultaneously, user stations have only two channel capability. Programs each user station to correspond with the same channels on the master stations.