JPH0344290A - Tip party earth level sending method - Google Patents

Abstract

PURPOSE:To facilitate the adjustment of longitudinal balance and to avoid the increase in the shape of a hybrid transformer by providing a tip party earth level sending circuit employing transistors (TRs) with a high impedance to an AC signal and a low impedance to a DC signal. CONSTITUTION:Tip party earth level sending circuits 42,43 are provided, which employ TRs whose impedance has a transmission loss of a specified value or below with respect to an AC signal and whose earth resistance with respect to a DC signal is within a specified range at the tip party earth level transmission. when an exchange side transmitter 4 detects the information of presence of tip party earth level, the tip party earth level sending circuit 42, 43 are connected to a tip line and a ring line connected to the exchange to send tip party earth level. The characteristic of a coil is realized by an electronic circuit employing TRs in this way to offer ease of adjustment of longitudinal balance and the size of the hybrid transformer is not increased.

Description

DETAILED DESCRIPTION OF THE INVENTION [Summary] This invention relates to a chip party ground transmission method used in identifying a calling subscriber in a joint subscriber telephone service provided via a subscriber-based PCM transmission device.

The purpose is to make it easy to adjust the vertical balance and to prevent the shape of the hybrid transformer from increasing.

A joint subscriber telephone service is provided via a subscriber-side PCM transmission device, and the subscriber-side transmission device provides information on the presence/absence of chip party grounding to recognize which subscriber is in the calling state. The information is sent to the exchange side transmission equipment via the PCM line, and the exchange side transmission equipment reproduces the state of the chip party grounding presence/absence based on the information and determines whether the two calling subscribers are connected to the chip party of the subscriber line. When the exchange recognizes whether it is a ring party, the impedance appears to be such that the transmission loss is below the specified value for AC signals, and the resistance to ground when sending chip party grounding to DC signals is within the specified range. A chip party grounding sending circuit configured using transistors is provided so that when the transmission device on the exchange side detects information that chip party grounding is present, + the chip party grounding is connected to the chip line and ring line connected to the tfA exchange. Configure to connect the sending circuit.

[Industrial application field]

The present invention relates to a chip party ground transmission method used in identifying a calling subscriber in a joint subscriber telephone service provided via a subscriber-based PCM transmission device.

Joint subscriber telephone service economizes subscriber lines.

Alternatively, in order to provide inexpensive telephone service, one subscriber line is shared by two or more subscribers.

For example, when two subscribers share one subscriber line, the chip party telephone is connected to the subscriber line's chip party, and the ring party telephone is connected to the ring party of the subscriber line. must be automatically registered for each subscriber, an identification section must be provided to identify the calling subscriber.

Here, one method of identifying the calling subscriber is to identify whether the chip party is grounded or not. At this time, it is necessary to easily adjust the vertical balance and to prevent the shape of the hybrid transformer from increasing.

[Conventional technology]

FIG. 3 shows an explanatory diagram of the joint subscriber telephone service provided via the subscriber system PCM transmission device.

Note that the chip party telephone and the ring party telephone are omitted except for the parts necessary for identifying the calling subscriber.

First, when the chip party telephone goes off-hook, the contact "I l + r 421□" turns on and becomes the dotted line state, and the DC power supply 13 (for example -48V) in the subscriber side transmission equipment 1 is turned on. The current from the + side is the chip party current detector 11. Contact r l I 1 + resistance R
11+contact r1. □, flows through the ring party current detector 12 in one example.

Also, the current from point A is resistance R1□+RIl+contact r
lI□ flows through the ring party current detector 12 to an example of the DC power supply 13. As a result, +IT < I+t
becomes.

Therefore, +IT is the current flowing through the chip party current detector 11 and +IR is the current flowing through the ring party current detector 12.

Next, when the ring party telephone goes off-hook, the contact rffi2□rlzz turns on and becomes the state shown by the dotted line, and the current from the + side of the DC voltage 13 is passed through the chip party current detector 11. rj2□, resistance R2□reZt+
It flows to one side through the ring party current detector 12.

As a result, b=I+t.

Here, if a threshold value α is determined such that IR-I7>α, then when the chip party telephone makes a call, the chip party current detector 11. The difference between the current values of the ring party current detector 12 is larger than α, and becomes smaller than α when the ring party telephone makes a call.

This allows the subscriber-side transmission device 1 to identify which party has made the call. In other words, since it is possible to determine whether or not the chip party is grounded (whether or not the chip party resistor R1□ is grounded),
This chip party grounding presence/absence information is encoded and PCM
It is sent to the exchange side transmission device 2 via the line.

In the exchange side transmission device 2, a decoder (not shown) extracts this information and reproduces the state of chip party grounding presence/absence as described later, so the exchange can recognize which party made the call. .

Next, FIG. 4 shows a block diagram of a conventional example.

In addition, the switch SW+ in the figure is off (solid line) when the footer is on, and on when the hook is off-hook, and the switch SW+ is off (solid line) when the information indicates no chip party grounding. It turns on when there is information.

In the figure, the above encoded chip party
The non-information is decoded by the encoder/decoder 21 in the exchange side PCM device via the PCM line, and the original chi-nobupati presence/absence information is taken out and added to the controller 23.

When the controller 23 detects that the input information is information indicating that the chip party is grounded, the controller 23 switches the switch SW.

Turn on SWz. However, when information indicates that the chip party is not grounded, only the SW is turned on. with this,
The chip party grounding presence/absence information is reproduced in the exchange side transmission device, and the exchange can recognize whether the calling party is the chip party or the ring party.

[Problem to be solved by the invention]

Here, during one call, always send out chip party ground (
When grounding the chip wire, the following points must be considered.

■ If the chip party ground is sent directly to the chip wire in FIG. 4, there will be a difference in impedance between the ground and the chip wire and between the ground and the ring wire, making it impossible to satisfy the vertical balance standard. As a result, the unbalance of the longitudinal voltage becomes large and the S/N ratio of the AC signal at the receiving point deteriorates.9■ In terms of DC, the tip line and the ring line must have low impedance. This is because there is a standard that the resistance to ground when the chip party leaves the ground is 9, for example, 1000 to 2600Ω.

■ In order to reduce transmission loss of AC signals 9, such as audio signals, it must have high impedance with respect to tip lines and ring lines.

Therefore, the impedance that satisfies these three conditions and looks at the exchange side transmission device from the exchange.

For example, in order to achieve 900 Ω + 2 μf (impedance matching), this has been realized using a hybrid transformer T1 using the characteristics of the coil as shown in FIG.

However, in this method, requirements for the number of windings, winding direction, core material, etc. for the hybrid transformer T1 become stricter, and the shape becomes larger.

In addition, to adjust the vertical balance, it is necessary to adjust the resistance R1 + RzO value, but if there are variations in the characteristics, the ratio of the two resistances R2 must also be adjusted, which poses two problems: it takes a lot of man-hours. .

It should be noted that, compared to a hybrid transformer for normal telephone service (without resistor RI+RZ+sW2), this hybrid transformer has a height of, for example, about 20χ, and is more than four times larger in length and width.

[Means to solve problems]

FIG. 1 shows a block diagram of the principle of the present invention.

In the figure, 42 and 43 appear to be impedances such that the transmission loss for AC signals is below the specified value, and for DC signals, the resistance to ground when sending out chip party grounding is within the current range. This is a chip party grounding sending circuit constructed using transistors.

When the exchange side transmission device detects the information indicating that chip party grounding is present, the chip party grounding sending circuit is connected to the chip line and ring line connected to the exchange, and the chip party grounding is sent out.

[Effect]

The present invention realizes the coil characteristics of low impedance for direct current and high impedance for alternating current using an electronic circuit using transistors, making it easy to adjust the vertical balance and preventing the size of the hybrid transformer from increasing. Make it.

〔Example〕

FIG. 2 shows a block diagram of the embodiment.

Here, the resistors Rn+ to R45 and the capacitor c++h transistor q1 are the constituent parts of the chip party ground sending circuit 42, and the resistors R46 to R47, the capacitor C2, and the transistor Q2 are the groove bottom part of the chip party ground sending circuit 43. The operation shown in FIG. 1 will be explained below.

First, the chip party ground sound from the encoder/decoder 21/
When the null information is applied to the controller 23, the controller sends out a corresponding control signal.

Then, switch SW is turned on (dotted line) and turned off.
Shows hook and becomes looped (busy).

If the calling party is the tip party, switch SW is turned on (solid line) and the tip party ground is sent to the tip line and the ring line.

Next, the operation of the electronic circuit that sends out the chip party ground will be described.

When the switch SW is turned on, 1, for example, -48V is applied to the transistor Q via the resistor R□+R4□+R43+R4S.

Since the voltage is applied to the collector and base of the transistor, an emitter current flows through the transistor and it becomes operational.

Generally, the voltage between the collector and the straw of a transistor is 3
The output side is designed to have high impedance for human AC signals when the voltage is higher than v, so the bias resistor, emitter resistor R4□~Ras,
Determine the value of RV.

Further, the base is grounded by a large capacity capacitor C3, and base grounding operation is performed for AC signals, so that the impedance on the output side becomes high.

Also, the impedance for the DC component is the ratio of the voltage applied to this circuit and the current flowing through it (which is approximately equal to the emitter current of transistor Q1).

This is made to have a specified low impedance.

Furthermore, for the @1 balanced standard, in order to equalize the ground impedance of the tip line and ring line for in-phase AC signals, both lines are grounded through the same circuit, but a variable circuit is used to make fine adjustments. A resistor RV is provided.

Note that the circuit operation of the transistor Q2+, resistors R46 to R41, and capacitor C2 is the same as the above operation.
Transformer T2 is for the normal telephone service mentioned above.
It is smaller than the conventional example.

This makes it easy to adjust the vertical balance, and the shape of the hybrid transformer does not increase.

〔Effect of the invention〕

As described in detail above, according to the present invention, the vertical balance can be easily adjusted and the shape of the hybrid transformer does not increase.

[Brief explanation of drawings]

FIG. 3 is an explanatory diagram of a joint subscriber telephone service provided via a subscriber system PCM transmission device, and FIG. 4 is a block diagram of a conventional example. In the figure, 1 is the subscriber side transmission equipment. 4 is a transmission device on the exchange side. 42 and 43 indicate chip party grounding circuits. C2 Asahikawa Fish Mouth/Tsuku Diagram No. 11 Sea Bream Hunting H Six-Shot Sickle Device Diagram Conventional Brotz/Fig. 7

Claims (1)

[Claims] Information on presence/absence of chip party grounding for recognizing which subscriber is in the calling state when a joint subscriber telephone service is provided via a subscriber-based PCM transmission device. is the subscriber side transmission equipment (1
) via the PCM line to the exchange side transmission device (4), and the exchange side transmission device reproduces the status of the chip party grounding presence/absence based on the information, so that the calling subscriber can connect to the subscriber line. When the exchange recognizes whether the chip party or ring party is, for AC signals, the impedance appears to be such that the transmission loss is below the specified value, and for DC signals, it looks like the impedance is such that the chip party is grounded. A chip party grounding sending circuit (42, 43) configured using transistors is provided so that the chip party grounding is within a specified range, and when the transmission device on the exchange side detects information indicating that chip party grounding is present, the chip connected to the exchange A chip party grounding sending method characterized by connecting the chip party grounding sending circuit to a wire or a ring line.