Abstract: The present invention discloses a standby power supply circuit for a 2-wire bus intercom system and an apparatus thereof. The standby power supply circuit is separated into two power supply modules; in which the first power supply module is a power supply to standby circuit and the second power supply module is a power supply to operation circuit; said power supply to operation circuit is switched off by a constant current switch when the device load is at the standby status; and said power supply to standby circuit comprises a constant current circuit whose alternating current impedance is very large. The solutions of the present invention achieve larger alternating current impedance for the 2-wire intercom system, which can offer sufficient power for many device loads both in the conditions of operation and standby statuses.

Abstract: The present invention discloses an electronic inductance circuit for the power supply of a 2-wire bus intercom system and a device thereof. The electronic inductance circuit comprises a main circuit path along an inductor and a source terminal and a drain terminal of a FET between the input terminal and the output terminal of said electronic inductance circuit, in which said inductor is connected to said source terminal of said FET; a resistor and a freewheeling diode individually connected to said inductor in parallel; and a secondary circuit path along a capacitor connected with a second resistor in series between said input terminal and said output terminal, which is connected to said main circuit path in parallel. The solutions of the present invention achieve larger direct current power supply for the 2-wire intercom system and stable alternating current impedance with fast response to the DC power supply.

Abstract: The present invention discloses a dual-channel analog door entry system and a method thereof. The dual-channel analog door entry system comprises two cables connected between the building gateway and the floor distributors, configured to transmit audio and/or video signals between the outdoor stations and indoor phones; the building gateway, configured to receive a call request from at least one of the outdoor stations, identify and assign an available cable as an intercom channel, send the call request to each of the floor distributors via the intercom channel, and switch the audio and/or video signals from the outdoor station to the available cable; at least one of floor distributors, configured to receive and forward the call request to a desired indoor phone, receive a call response from the desired indoor phone if the desired indoor phone is available, and switch the audio and/or video signals from the available cable to the desired indoor phone.

Abstract: The present invention discloses a standby power supply circuit for a 2-wire bus intercom system and an apparatus thereof. The standby power supply circuit is separated into two power supply modules; in which the first power supply module is a power supply to standby circuit and the second power supply module is a power supply to operation circuit; said power supply to operation circuit is switched off by a constant current switch when the device load is at the standby status; and said power supply to standby circuit comprises a constant current circuit whose alternating current impedance is very large. The solutions of the present invention achieve larger alternating current impedance for the 2-wire intercom system, which can offer sufficient power for many device loads both in the conditions of operation and standby statuses.

Abstract: The present invention discloses a dual-channel analog door entry system and a method thereof. The dual-channel analog door entry system comprises two cables connected between the building gateway and the floor distributors, configured to transmit audio and/or video signals between the outdoor stations and indoor phones; the building gateway, configured to receive a call request from at least one of the outdoor stations, identify and assign an available cable as an intercom channel, send the call request to each of the floor distributors via the intercom channel, and switch the audio and/or video signals from the outdoor station to the available cable; at least one of floor distributors, configured to receive and forward the call request to a desired indoor phone, receive a call response from the desired indoor phone if the desired indoor phone is available, and switch the audio and/or video signals from the available cable to the desired indoor phone.

Abstract: The present invention discloses an electronic inductance circuit for the power supply of a 2-wire bus intercom system and a device thereof. The electronic inductance circuit comprises a main circuit path along an inductor and a source terminal and a drain terminal of a FET between the input terminal and the output terminal of said electronic inductance circuit, in which said inductor is connected to said source terminal of said FET; a resistor and a freewheeling diode individually connected to said inductor in parallel; and a secondary circuit path along a capacitor connected with a second resistor in series between said input terminal and said output terminal, which is connected to said main circuit path in parallel. The solutions of the present invention achieve larger direct current power supply for the 2-wire intercom system and stable alternating current impedance with fast response to the DC power supply.