Telephone controlled lock release arrangement

Details Telephone controlled lock release arrangement Telephone controlled lock release arrangement

1977-10-21

1978-09-12

Claffy, Kathleen H.

179 39, 179 1H, H04M 1100

Patent

active

041139860

ABSTRACT:
Circuitry is disclosed for the automatic dial-up of an apartment telephone from a lobby telephone to provide voice communication therebetween via a central switching office and for controlling the establishment of a switched signaling path through a switching network independent of the central office and then the unlocking of the lobby door over that switched path. The circuitry includes a trunk circuit for connecting the lobby telephone set to the central office and service circuits for detecting and processing call on/off-hook and ring signals as well as lobby door lock release signals from the called apartment. Distinctive tone bursts are applied by a service circuit through the switched path to notify the called apartment dweller of a lobby originated call.

REFERENCES:
patent: 2377850 (1945-06-01), Blakeslee
patent: 3342944 (1967-09-01), Barbato et al.
patent: 3406260 (1968-10-01), McEowen
patent: 3428753 (1969-02-01), Pfleiderer et al.
patent: 3484561 (1969-12-01), Matthews
patent: 3557318 (1971-01-01), Buonsante et al.
patent: 3917911 (1975-11-01), Lesher
patent: 3947641 (1976-03-01), Trell

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