CN2252458Y - Two-wire building space intercom - Google Patents

Abstract

The utility model relates to a two-wire building space intercom, which is composed of a microphone, a talking and ringing amplifying circuit of a loudspeaker and a hook switch. The utility model is characterized in that a key switch is bridged between two circumscribed leading wires, and an input terminal of the talking and ringing amplifying circuit is also provided with a full wave rectifying circuit. The hook switch is a three-reed two-contact switch of which the two contact reeds are connected. The two-wire building space intercom is monitored by a switchboard with an SCM and can achieve the functions of ringing, talking, remote control unlocking, etc. The utility model has the advantages of simple circuit, convenient installation, etc. The polarity of the two circumscribed leading wires does not need to be distinguished. When short circuit fault occurs on the two circumscribed leading wires, the use of the switchboard and other extension sets can not be influenced.

Description

A kind of two-wire system building talkback extension set

The utility model is a kind of building talkback extension set, particularly a kind of two-wire system building talkback extension set.

The existing used extension set of various building conversational systems mostly is multiple-way system, and its house lead in number generally needs four to five, and each line all has definition, wants careful corresponding during installation, and system just can normally move, and installs very inconvenient.When the mutual short circuit of these lines, whole system will be paralysed.

The purpose of this utility model provides the extension set that a kind of house lead in only needs two cores.Its house lead in can be as telephone wire not polarity link to each other with the intercommunication extension set.Under the talk-back host with single-chip microcomputer is supported, realize ring, intercommunication and remote-control unlocking function.When the mutual short circuit of two heart yearns of house lead in, can not influence main frame and the every function of other extension sets yet.

The purpose of this utility model is achieved through the following technical solutions.

The design is the rectification circuit of input increase at conversation and ring amplifying circuit, and between two external lead wires, have a short circuit key switch, simultaneously the switch hook of extension set is changed into three reeds, two contact switchs that a kind of two contact reeds are connected.Like this, extension set can correspondingly reflect three kinds impedance variation when on-hook, off-hook and unlocking condition, and main frame will be finished corresponding monitoring program according to these variations, thereby realizes the purpose of this utility model.

The utility model circuit is succinct, and two external lead wires are polarity not, installs very conveniently, can not influence talk-back host and other user's use during two line short circuits.

Further elaborate concrete structure of the present utility model and operation principle below in conjunction with accompanying drawing.

Fig. 1 is the extension set structured flowchart

Fig. 2 is the extension set schematic diagram

Fig. 3 is one of a switch hook structure diagrammatic sketch

Fig. 4 is two diagrammatic sketch of switch hook structure

Fig. 5 is that extension set is when selected and the main frame connection diagram

With reference to Fig. 1, this extension set is made up of conversation and ring amplifying circuit A, switch hook S1, rectification circuit B, key switch S2, wherein rectification circuit B is connected in the input of conversation and ring amplifying circuit A, and key switch S2 is connected across between external lead wire R, the T.

With reference to Fig. 2, conversation and ring amplifying circuit A, the amplifying circuit of being made up of microphone MIC, loudspeaker SP and triode T1, T2 is constituted; Rectification circuit B, the full-wave rectifier of forming by diode D1-D4, constitute; Three reeds, two contact switchs that switch hook S1 is made up of reed 1,2,3, wherein contact reed 2,3 is connected; Key switch S2 is a kind of compression joint type short switch.

With reference to Fig. 3, one of structure of switch hook S1 is that reed 1 is the movable contact reed, and reed 2,3 is a back contact spring, and reed 2 is connected with reed 3.

With reference to Fig. 4, the another kind of structure of switch hook S2 is that reed 1 is the stationary contact reed, and reed 2,3 is the movable contact reed, and reed 2 is connected with reed 3.

With reference to Fig. 5, C represents the utility model among the figure---and the two-wire system extension set, all the other are the relative section with main frame of single-chip microcomputer.

With reference to above-listed each figure,

1, send the words principle: voltage is added on the extension set C through RO during conversation, and behind rectification circuit B, F, G two ends are added with a voltage.We establish the G point voltage is 0, and the F point voltage is V1, and V1 gives bias voltage of triode T1 through R1, and the existence of R2 makes the emitter of T1 that a voltage be arranged, and is made as V2.V2 makes on the resistance R 3 and produces voltage for triode T2 provides biasing, is made as V3, and V3 provides biasing through R4 for microphone MIC.Speech through the amplification of T1, produces telecommunication signal through the base stage that C1 is added to T1 on the F point.

2, talked about principle: the voice signal from talk-back host is added in R, and the T end is delivered to F, G two ends through rectification circuit B and hook switch sheet switch S 1, supposes that voice signal is a sinusoidal signal, is superimposed upon on the V1.R4 is greater than R3.During the positive half cycle of voice signal, electric current mainly forms charge circuit through C2, R3 and whole loudspeaker SP; During negative half period, C2, T2, R3 and loudspeaker SP form discharge loop, just form a complete sinusoidal signal like this on the loudspeaker.

3, anti-sidetone principle: when microphone MIC speech increased, the voltage V1 that F is ordered descended, the also corresponding decline of V3 this moment, and the variation that then is reflected on the loudspeaker SP will diminish, and vice versa, thereby play anti-sidetone effect.

4, ring principle: ringing pulse signal GM is added in R, T two ends, and behind rectification circuit B, F, G end obtains pulse voltage.Ringing pulse signal GM ends T3 during positive half cycle, during negative half period, makes the T3 conducting.When T3 ended, C2, R3 and loudspeaker SP formed charge circuit, and C2 finishes charging.During the T3 conducting, R, T both end voltage are 0, and C2, T2, R3 and loudspeaker SP form discharge loop.When extension set C was selected, T4 was conducting, and voltage acts on R and T two ends through RO, and the ringing pulse signal GM that single-chip microcomputer sends in the main frame is added in the base stage of triode T3 simultaneously.R, T line-to-line produce music pulse, and the loud speaker SP in the selected extension set sends the music ringing tone.During off-hook, the reed 1 of switch hook S1, does not all contact with reed 2,3 to the process of reed 3 for some time from spring leaf 2 bullets, is equivalent to open circuit A and makes R, T two ends become open-circuit condition, talk-back host can be discerned this variation, stops ring and enters voice procedure.When the on-hook of extension set conversation back, the reed 1 of switch hook S1, does not all contact with reed 2,3 again to the process of reed 2 for some time from reed 3 bullets, makes talk-back host identification user on-hook.

5, the principle of unblanking: the user can press S2 as unblanking, and makes it closed, short circuit R, T two lines, and this moment, R, T became short-circuit condition, and main frame is discerned this variation, carries out the program of unblanking.

When extension set was not selected, the T4 among Fig. 5 ended, and R, T two ends do not have voltage, and R, T two lines open circuit or short circuit are all meaningless.Just can not influence main frame and other extension sets yet.

When extension set just selected, and this moment R, between the T line state have three kinds may: (1) R, T two lines are in open-circuit condition always, and main frame knows that just extension set does not insert, and enter the open fault attention program; (2) R, T two lines are in short-circuit condition always, and main frame can not enter the program of unblanking, but enter the short trouble attention program; (3) be connected to extension set between R, T, enter normal ringer, talking state.

Claims (4)

1, a kind of two-wire system building talkback extension set, by the conversation that comprises microphone (MIC), loudspeaker (SP) and circuit (A) is amplified in ring and switch hook (S1) is formed, it is characterized in that, between external lead wire (R) and external lead wire (T), a key switch of cross-over connection (S2), input at conversation and ring amplifying circuit (A) has rectification circuit (B), three reeds, two contact switchs that described switch hook (S1) is made up of reed (1), reed (2) and reed (3), wherein contact reed (2) is connected with contact reed (3).

2, building talkback extension set according to claim 1 is characterized in that, rectification circuit (B), and the full-wave rectifier of being made up of diode D1-D4 is constituted.

3, building talkback extension set according to claim 1 is characterized in that, its reed of described switch hook (S1) (1) is the movable contact reed, and reed (2) and reed (3) are the stationary contact reed.

4, building talkback extension set according to claim 1 is characterized in that, described switch hook (S1), and its reed (1) is the stationary contact reed, reed (2) and reed (3) they are the movable contact reed.

Images