INTERCOM AND LOCKING DEVICE Russian patent published in 1997 - IPC

FIELD: intercommunication systems. SUBSTANCE: device has n intercom-calling sets $$$, n locks $$$, n lock release sets $$$, switching unit 4, m subscriber sets $$$. Outputs of lock release sets $$$ are connected with first inputs of intercom-calling sets $$$ which by first outputs are connected with locks $$$ and by their second outputs and inputs they are connected with switching unit 4, and its second inputs and outputs are connected with subscriber sets $$$ through communication busbar made as real pair of wires. EFFECT: high efficiency. 1 cl, 1 dwg