JPS5854708B2 - Tone sound transmission method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention generally relates to a tone transmission system, and in particular, in a telephone switching network, calls by non-important subscribers are regulated during abnormal call congestion, and when non-important subscribers attempt to make calls, The present invention relates to a talk sound transmission method for notifying a subscriber by sound that calls are being restricted.

First, the concept of the talk sound sending circuit will be explained with reference to FIG.

This circuit is currently used in DIO type automatic exchanges.

In Fig. 1, SUB is a telephone terminal, LR is a line relay for detecting a call, lc is a contact point of a line cut relay (not shown) that operates by a line cut signal, T is a wire for sending out a talkie, and O8C is a contact point for a line cut relay (not shown) that operates by a line cut signal. The talkie sound source, D and R are Zener diodes and resistors for setting the secondary side of the talkie wire to -5V, and C6 is the cut-off contact.

The reason for setting it to -5V is to conduct the diode inserted in series with the subscriber line in the push-button telephone to produce a talking sound, and -48V requires a wire with a large current capacity. be.

In Fig. 1, when there is abnormal call congestion, a line cut signal from a monitoring test device (not shown) is used to cut the line to I-I.
When the J tray operates, the LC contact is connected to the A side, and a non-important subscriber makes a call, G (B line) → C6 contact (B line) → S
U B-+CO contact (A line) →-+ L R-) l
A loop is formed between the C contact → the secondary side of the talkie wire ring → the R+48 ■ power supply, and a direct current flows through the diode inside the telephone, and through the same loop, the talkie sound from the talkie sound source O8C flows through the telephone terminal, giving the subscriber a talkie tone. can be heard.

The current that flows at this time becomes less than the impressive current value of LI (, due to the action of the resistor R and the Zener diode D, so when the subscriber line scanning device detects a call, it is considered to be in a non-call state, and the call is regulated. .

Next, the conventional technology of the current switching type direct scanning system to which the present invention is applied will be explained with reference to FIG.

In the case of this scanning method, the scanning master of the subscriber line scanning equipment)
The IJ Lux line is directly connected to the subscriber line, and the talk sound transmission circuit associated with call regulation is also connected to the subscriber line, so when sending talk sound from the A line side, the subscriber line scanning device is required. A number of problems arose in the design, and as a result, the talking sound was sent from the B line side.

In the circuit of FIG. 2, the line relay LR for detecting call origination, which is provided for each subscriber in FIG. 1, is removed, and this is replaced by the diode D1. D2 and resistors RM, RB, etc. are substituted.

In Figure 2, 5TJB is a telephone terminal, Dl and D2
is the diode for forming the scanning matrix I-IJ flux, S
A is a sense amplifier, RM is a matrix resistor to limit the current flowing to the scanning matrix circuit, RB is a bleeder resistor to increase the current flowing to the terminal side, LD is a wire for selection drive, LS is a call detection DB selects the bias on the call detection side, a bias diode to raise it higher than the drive side, O8C is the talkie sound source, T is the talkie sending line, LT is the blocking line for direct current flow. , r is a resistance for restricting the flow of direct current to the talkie wire, and lc' is a contact point of a line cut relay (not shown) operated by a line cut signal.

Note that the portion A surrounded by the dotted line is actually configured in a matrix shape as A', but is shown as A for simplicity of illustration.

During normal call processing, the llc contact is open and no talkies are sent, but when outgoing calls are restricted, a line cut relay (not shown) is activated by a line cut signal from a monitoring test device (not shown). The l'/c contact is closed.

Is there a talking sound due to the closing of the z′C contact? @G (B line) → G (secondary side) -) r-) CO contact (B line) -) SU
f3-+ C0 contact (A line) a! ? ]
→48V power supply loop, and the subscriber of the telephone terminal can know that outgoing calls are restricted.

Further, by means of a circuit (not shown), when calling is restricted, non-important subscribers are not scanned, and calling is restricted.

The operation of the circuit shown in FIG. 2 to detect a call is to selectively drive the current flowing in the arm on the side a in the figure, which includes the diode D1, by the LD when the subscriber makes a call. The switch is switched to the side arm, and this is detected by the sense amplifier SA via the LS.

However, in Figure 2, if line B falls to the ground (indicated by the broken line), most of the sound will flow into the ground where the impedance is low, and the sound will no longer flow into the loop described above. Therefore, the sound is not transmitted to the telephone and the talk sound cannot be heard.

Moreover, in FIG. 2, multiple terminals are multi-connected to one talkie wire, so if one telephone falls to the ground, the talkie sound will no longer be heard on all the multi-connected telephone terminals of the subscribers.

Therefore, the present invention aims to improve the above-mentioned drawbacks of the prior art, and its object is to provide a talk sound transmission system that reduces the range of influence of ground faults on talk sound disturbances.

A feature of the present invention for achieving this object is that, in the subscriber circuit of an automatic exchange that sends a talk sound from the B line to non-important subscribers when outgoing calls are restricted, the subscriber circuit connected to one talk sound generation source is The method is to divide the B line into a plurality of groups and connect the B line of each group to the talking sound source via a diode or resistor.

This will be explained below with reference to the drawings. FIG. 3 is a configuration diagram showing an embodiment of the present invention. In FIG. 2, telephone terminals SUB connected to one talkie transmission wire T are divided into several groups G1 to Gn, each group being Dividing diodes DD1 to DDn are inserted between the sound coil and the talking wire T, and the diodes DD1 to DDn have a forward voltage drop that does not cause conduction with the alternating current signal of the talking sound.

For this purpose, each diode may be a series connection of a plurality of diodes.

It is now assumed that a B line ground failure occurs in one telephone terminal belonging to group G1 to which diode DD1 is connected.

In that case, if there is no difference in ground potential between the ground potential of G in the exchange and the ground where the B line has fallen to the ground, diode DD1 will be cut off, and the telephone terminal of group G□ connected to DDl will receive a No sound can be heard, but the talking sound can be heard from the group of telephone terminals connected to other diodes.

Also, even if there is a difference in ground potential between the G ground potential in the exchange and the ground where the B line has fallen to the ground, which is greater than the diode conduction, there is usually a certain amount of line resistance between the diode and the ground. Therefore, the talk sound can be heard on other groups of telephone terminals.

In other words, there are many telephone terminals that are connected in multiple ways, and the impedance of the terminal side as seen from the wire is low, so even if the line is grounded due to a minimum line resistance of several ohms, a drop in the level of the talking sound on the terminal side will not be a problem. .

Line resistance within a few ohms causes the line to fall to the ground only within the exchange, and in this case, there is no ground potential difference, so the diode is cut off.

In the case of a ground fault outside a switching center where there is a difference in ground potential, there is a line resistance of several ohms or more, so other groups can still hear the talking sound.

Therefore, the diodes DD1 to DDn can be replaced with resistances that are approximately equal to these forward resistances.

The number of groups and the number n of diodes are determined by the number of telephone terminals allowed as a fault propagation range.

The present invention is particularly effective in the case of a current switching type direct scanning system, but it is clear that it is also an effective means when transmitting a talk sound from the B line even in the case of an already known indirect scanning system. It is.

As a countermeasure against Naori line ground failure, it is possible to create a Toki line ring T for each group, but the method according to the present invention is
It is superior in terms of economy and mounting space.

As explained in detail in the embodiments above, in the present invention, subscribers are divided into a plurality of groups, and the B line of each group is connected to the talkie transmission wire via a diode or resistor. It is possible to reduce the influence of earth-falling disturbances on the tone sound.

[Brief explanation of the drawing]

Figure 1 is an explanatory diagram of the principle of a conventional talk sound transmission circuit, Figure 2
The figure shows a block diagram of another conventional talk sound transmission circuit, and FIG. 3 is a block diagram of a talk sound transmission circuit according to the present invention. SUB...Telephone terminal, DD□~f) D n
...Diode, G□~Gn...Group, T...Talking transmission coil.

Claims (1)

[Scope of Claims] 1. In a subscriber circuit of an automatic exchange that sends a talk sound from the B line by non-important subscribers when calling is restricted, subscribers connected to one talk sound generation source are divided into a plurality of groups. death,
A talking sound characterized in that the B wires of each group are connected to the talking sound source through diodes having a forward voltage drop that does not conduct with the alternating current signal of the talking sound, thereby reducing the range of influence of the B line earth disturbance. Sending method. 2. The talk sound transmission system according to claim 1, wherein the diode is a plurality of series-connected diodes.