Pro Intercom AD920 Balanced/Unbalanced Interface

Balanced / Unbalanced System Interface Adapter The AD920 Balanced/Unbalanced Interface provides impedance matching and signal conversion between a balanced intercom circuit and an unbalanced intercom circuit. Both channels become audio and light-signal compatible. Power may come from either intercom circuit or from both simultaneously. This is particularly useful for production crews wanting to use their unbalanced system with a balanced 'house' system. Each circuit to be used will require its own AD920. There are no user-operated controls. Connection is via clearly marked 3-pin XLR connectors; 1 female, 1 male. The first intercom systems used in entertainment applications were simply strings of telephone operator headsets strung together in parallel along a pair of wires powered by a set of batteries. There was no individual volume control and no signaling system. As electronic equipment began to be used on the stage and throughout the venues, these systems rapidly became inadequate.