The Bogen CA-Series Call-In Switches are attractive, functional units for call-in from classrooms or other staff locations to Bogen’s PI35A and SI35A Intercom Systems, Multi-Graphic© Series 115B, 2223, and 2233 Institutional/School Communication Systems, and Multicom 2000® Administrative Communication Systems. The switch is a two-position, rocker-type, single-pole, normally open switch. When pressed, the switch energizes the corresponding annunciator lamp and the call-in tone at the room selector panel, and maintains this condition after the switch is released and until the call is acknowledged by the operator.