INTERCOM-CONTROLLING SYSTEM Russian patent published in 1994 - IPC

FIELD: wire electric communication. SUBSTANCE: intercom-controlling system has central unit 1, N apartment units 2, unit 3 of dialing of number of apartment, unit 4 of conversion of dialed number to code, digital display unit 5, code converter 6 in amplitude-modulated signal, transmitter 7 of central unit, matching unit 8 of central unit, receiver 9 of central unit, code recognizer 10 of central unit, unlocking unit 11, intercom unit 12, receiver 13 of apartment unit, intercom-instruction unit 14, code recognizer 15 of apartment unit, transmitter 16 of apartment unit, matching unit 17 of apartment unit. EFFECT: no need for laying of separate communication line as existing domestic lighting system is sufficient for its operation. 1 dwg