| 摘要 |
FIELD: telephony; calling, intercommunication, and unlocking entrance door in apartment houses. SUBSTANCE: system has calling unit (door intercom, entrance door unlocking unit, dialer), control unit, n- apartment units, where n is number of entrance apartments, and communication lines. Novelty is that control unit is made in the form of two decade switchboards and multichannel current switch. EFFECT: improved design. 2 dwg
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