JPS6350295A - Circuit for detecting collision of incoming and outgoing calls - Google Patents

Abstract

PURPOSE:To surely detect outgoing and incoming calls by connecting both a light emitting diode connected reversely a 1st diode and a 2nd diode that is connected in the reverse direction of said light emitting diode in parallel to a parallel circuit consisting the 1st diode and a 1st resistance only in an outgoing mode. CONSTITUTION:In the outgoing mode a contact point 12 is connected to a make side A by outputting a control signal, and a diode 10 and a resistance 11 are functioned. If a trunk line is not in an incoming state, a current is conducted through the following route: L1 a transformer 9 the diode 10 the contact point 12 a Zener diode 4 L2. However a current is not conducted to a light emitting diode 1a through said route, and a collision is not detected. The current conducted at that time is large enough to activate a station exchange. Afterwards, a contact point 6 is closed. By returning the contact point 12 to a brake side B, and opening/closing the contact point 6, a dial pulse is transmitted. An outgoing and incoming call collision detection means(CPU, for instance) detects the collision of incoming and outgoing calls, by judging from the fact that a potential at a point C changes to 0V from 5V. After the detection, a dead trunk line is searched to dial.

Description

Detailed Description of the Invention (() Industrial Field of Application The present invention is a terminal device connected to a single-station switching facility and having an automatic calling function, in which a call from the terminal device and an incoming call from the station 1 collide. This invention relates to a call/call collision detection circuit that detects a call/call collision.

lcF+ Conventional technology As a conventional single call/receive collision prevention circuit, the
Publication No. 756 I: Shown and has its own thing. In this circuit, a minute current is passed through the station line so as not to stop the calling operation of the station exchange equipment when one call is made.

This tiny current is used to operate a relay to prevent collisions, but this requires a special highly sensitive relay. Due to the configuration of the first circuit, it cannot have any functions other than collision monitoring.

(/→ Problems to be Solved by the Invention The present invention solves the problems of the prior art, which requires a highly sensitive relay and has only a single function.

The present invention provides a circuit constructed of semiconductor components and having functions other than a collision monitoring function.

B) Means for Solving Problems The present invention is a call collision detection circuit in a terminal device having both calling and receiving functions for one station line C2. A first resistor is connected in parallel to the diode in order to cause current to flow in the opposite direction to that of the first resistor. a light emitting diode connected in the opposite direction to the first diode; a second diode connected in parallel in the opposite direction to the light emitting diode; It consists of a resistor, a phototransistor paired with the light emitting diode, and a transmission/reception collision detection circuit.

A light emitting diode connected in the opposite direction to the first diode and a light emitting diode connected in the opposite direction to the first diode in a parallel circuit consisting of a first diode and a first resistor.
Since two parallel C-connected fins and a second diode are connected, when an incoming call is received during a call, current flows from the light emitting diode through the resistor, and the incoming call can be detected by lighting up the first light emitting diode.

In addition, since a resistor is provided in parallel with the second diode at times other than the first transmission, the level of the detection current of the first light-emitting diode can be increased.When the first transmission is made, this resistor is disconnected by a relay contact and connected to the first diode. The detection current can be secured by covering the decrease in the current value due to the nest 1 resistor provided in parallel.

(f) Embodiment FIG. 1 shows the central office line circuit of a nine-yard main switch using the incoming and outgoing call collision detection circuit according to the present invention and the embodiment (A1 is the entire circuit e,
t01 is a diagram showing an incoming call detection section. (1) is a protection circuit that prevents damage to the external surge voltage (2)
a) is a light emitting diode of the photocabuku, and (3) is a resistor that limits the current flowing to the light emitting diode. (4) has the function of protecting the light emitting diode (2a) when a reverse voltage is applied to the light emitting diode (2&)C, and when the forward voltage of one light emitting diode (2a) is less than 7]0C: It is a nine-zener diode that has the function of limiting the voltage applied to the light emitting diode (21!L) and the resistor (3).(5) is the light emitting diode (2a) and the resistor (3).
This is a resistor that increases the Threnjord level of the output current.

(6) is a nine-relay contact that forms a loop for telephone calls and also has the function of generating dial pulses; (7)
) is a capacitor that has the functions of blocking direct current and protecting the relay contact (6) by combining it with the resistor (8). (9) is a nine transformer that has both a balanced/unbalanced conversion function and a loop maintenance function by passing a direct current. αG is a diode to create a transmission loop when transmitting, (Ill is a light emitting diode (2a
) A resistor for flowing current.

α2 can be used to create a transmitting loop or a light emitting diode (2
1L), the diode αa and resistor αD are connected to the Zener diode (4) and the light emitting diode (2a)l.
: The relay contact to be connected (A+ is the make contact, (Bl is the break side contact. This relay contact α3 is connected to the break side (Bl) except when transmitting. (21)) is the light emitting diode (2 &) 7 optocoupler phototransistor paired with 13 is a pull-up resistor.

2 is an incoming call detection circuit that operates based on the detected calling signal, and a constant voltage (+5V) is applied to it.

For station lines that are not receiving calls, Ll is earth C0V).

Ll is polarized to the battery (48v).

On the other hand, for the central office line with 1 incoming call, Ll is connected to the battery aBv), Ll
is the polarity of earth energy (Ov). The present invention utilizes this difference in polarity. C: The operation will be described below.

When sending,! , Send a control signal to contact (13) and make (III (connect to A+, diode CI
Make G and resistance hυ function. If the office line is not in an incoming call state at this time, the current flows through the following path. L1→1→transformer)→diode α■→contact I′1→Zener diode (4)→L2 In this path, no current flows through the light emitting diode (2a), and fA sudden detection is not performed. Also, the current flowing at this time is of sufficient value to start up the station exchange equipment. After this, contact (6) is closed and contact C1z is broken (i
ll (Return to Bl and open/close contact (6) [:
Send out a dial pulse.

On the other hand, if the first station line is already in an incoming call state when the contact r12 is connected to the Megging extension 1 (A), the current flows through the next path.

L2 → Resistor (3) 1 Light emitting diode (2a) → Contact 0z
→ Resistor 01) → Transformer (9) → L (1) Note that whether or not current flows is determined by the value of resistor a1J, so it is necessary to set the C2 resistance value so that current flows in the upper path. When current flows, the result is a phototransistor (2
b) changes from the cut-off state to the conduction state, and the output means detects a call collision when the potential of a, 6 changes from 5V to (1'Vl). The call is made by searching for and connecting to the local office line.

If the value of the resistor (ill) is too small, the calling operation of the single-station exchange equipment will be stopped, so in the end, the phototransistor (2") will be in a conductive state!: Sufficient N to transfer the current to the light emitting diode (2a) The value of the resistance QllO must be set so as not to stop the calling operation of the single station switching equipment at the same time as the current flow.As mentioned above, by setting the resistance Qυ to an appropriate value, it is necessary to avoid a collision with an incoming call when the first call is sent. In addition, if there are N calls, the 6-call loop is not formed, so it is possible to move on to incoming call detection processing without completely stopping the calling operation of the 1-station main switching equipment. I can do it.

come.

Next, the incoming call response detection function of this circuit will be explained.

When making a call, create a call loop and send out a dial pulse 1
The terminal waits for a response from the incoming signal, but when the terminating station responds, the 5-station switching equipment operates to reverse the polarity of the station line on the calling side. As a result, the circuit C current flows through six paths.

■ L2 → Zener diode (4) - contact (6) → transformer (9) → L1 ■ L2 → resistor (3) 1 light emitting diode (z&) → contact (6) → transformer (9) → L1 ■ L2 → resistor ( 5) -→Contact 0→Contact (6)→Transformer (9)→L1 As a result, as shown in Figure 1, the phototransistor (21) changes from the cut-off state to the conduction state, and as described above, an incoming call is received. A response is detected and the S and M responses are used for providing billing information, etc.

Next, the ability of this circuit to detect a calling signal will be explained.

2 When a call arrives, a 16Hz, 75yrma calling signal is sent to L2 from the 0 station switching equipment. Since the contact (6) is open, it is insulated from a direct current perspective.

An alternating current C)i loop is formed from the capacitor (7) C, so the calling signal passes through. This call signal causes
When L2 has a higher potential C2 than Ll, the light emitting diode (
Current flows through 6 as a result of phototransistor (2a).
b) changes from the cut-off state to the conduction state. L2? 7I, 1
When becomes higher, current no longer flows through the light emitting diode (2&), and as a result, the phototransistor (2b)
returns to the cut-off state.

The weak phototransistor (2b) repeats the cutoff four times in a period of 16H2, and this phenomenon is detected by the incoming call detection circuit q↓ of the first crisis period.

This incoming call detection circuit is constructed using, for example, a counter circuit.

Here, the resistor (51) is used to bypass the current flowing through one light emitting diode (2!L) and the resistor (3), and to raise the threshold level of the detection current.

This has the function of preventing external noise from being mistakenly detected as a calling signal. However, when the above-mentioned function of detecting N and others is carried through the light-emitting diode (2a), the current flowing through the light-emitting diode (2a) is limited by the resistance σD, and its value is minute. Therefore, if the resistor (5) is attached, current will not flow through the light emitting diode (2a) C: and it will not be possible to detect one incoming call sufficiently.For this reason, when detecting a collision of five incoming calls.

contact! 1 to disconnect resistor (5), L2. L1
All of the two minute currents flowing between them are passed through the light emitting diode (2a), and as a result, the threshold level of the detection current is lowered. Note that a diode may be used instead of the Zener diode (4).

In this way, the present invention can configure a call collision detection circuit using semiconductor components, so it does not require a highly sensitive relay and also has functions for calling (signal pressure detection and incoming call response detection). It is possible to

(g) Details of the invention According to the present invention, the explanation will be as follows at the time of one outgoing call.

If there is no collision with an incoming call, the central office switching equipment will be activated from the time of the call, and if the first incoming call collides with the next, a loop will not be formed, so it is possible to detect the incoming call without stopping the calling operation of the central office switching equipment. You can move on to processing.

Furthermore, when a call is made, the incoming call response can be detected by reversing the polarity of the 1-station line when the called party responds. It is possible to prevent erroneous operation due to external noise in the ringing signal when a 1N call is made.

[Brief explanation of the drawing]

FIG. 1 is a diagram of the central office line circuit of a private branch exchange using the incoming/outgoing call collision detection circuit of the present invention, (A) is the overall circuit diagram, and (A) is a diagram showing the incoming call detection section. (1) ...protection circuit, (2!L)...light emitting diode, (213)...phototransistor, (3),
C51, (81, QlJ. a3...Resistor, (4)...Zener diode,
(61, (1? I...S L/- connection A, f71... Capacitor, t9+... Tokuns, C1O...
・Die code, 041...Incoming call detection circuit.

Claims (1)

[Claims] (1) In a call collision detection circuit for a terminal device that has both the function of sending and receiving calls to a central office line, the first diode that creates a calling loop for the central office line when making a call, and the first diode in the opposite direction. a first resistor connected in parallel to the first diode to allow current to flow through the first diode, and the first diode connected to a parallel circuit consisting of the first diode and the first resistor via a relay contact only when transmitting a signal; a light emitting diode connected in the opposite direction, a second diode connected in parallel in the opposite direction to the light emitting diode, a second resistor provided in parallel with the second diode except when transmitting, and the light emitting diode a phototransistor paired with a phototransistor, and call collision detection means for detecting a call collision based on the output of the phototransistor, and when making a call, a parallel circuit consisting of the first diode and a first resistor is connected to the relay contact to cause the light to emit. The light emitting diode is connected to a parallel circuit consisting of a diode and the second diode to eliminate the influence of the second resistor, and the phototransistor is operated by lighting the light emitting diode, and the call collision detection means detects a call collision, and the call is transmitted. A call collision detection circuit characterized in that the detection current level of the light emitting diode is made high by the second resistor at times other than the above.