JPH0352720B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a subscriber telephone device such as a button telephone device and a PBX.

Conventionally, when a relay, a photothyristor, or the like is used as a communication path element in a button telephone device as one of this type of device, the communication loss is small and necessary technical standards can be satisfied. However, such communication path elements are very expensive, and a large number of communication path elements are used in button telephone devices with a medium capacity (5 office lines, 12 telephones) or higher.
Overall, there aren't many advantages. In recent years, with the development of semiconductor technology, very cheap C-
MOSIC switches became available and were used as pass elements in button telephone equipment, but because of their low voltage resistance and high on-operation resistance, the central office line and telephone sides were electrically separated by a transformer. The need arose. Moreover, due to transformer coupling,
Call loss occurs, and the standard telephone circuit network (e.g. 601 type telephone) cannot meet the technical standards of the Telephone Corporation, so a special telephone circuit network (2 transformer circuit or 3 core transformer circuit) ) to compensate for call loss, but because the circuit network was an LCR passive element, it had the drawback that it could only compensate up to a certain level. Furthermore, there are problems such as instability compared to the side-tone characteristic 601 circuit network, and there are cases where the telephone is connected to a straight central office line so that it can make and receive calls during a power outage. In order to satisfy the characteristics and communication performance, it was necessary to switch the balanced circuit network.

FIG. 1 is an example of a block diagram of a conventional all-button device. When the power is on, the office lines L ₁ to _Lo are connected to the power failure switching circuit 3 provided in the main device ME, the office line unit 4, the input transformer 5, the C-MOSIC crosspoint switch 7, the output transformer 8, and the communication current. Supply circuit 9b, power outage switching circuit 9a and station line selection switch
LK ₁ ...Connected to the button telephone TEL through LK _o . The telephone TEL includes a PB dial/DP dial originating circuit 20, a circuit network 21, and a switch 30. The balanced circuit network 31 is for compensating for call losses (mainly losses of 5, 7, and 8) when electricity is on, and 32 is for satisfying call characteristics (no call loss) during power outages. . At the time of a power outage, the power outage switching circuits 3 and 9a switch over the office line and connect it directly to the telephone, and the balanced circuit network 32 is switched by the power outage switching circuit 33. Also, PB dial/
The DP dial transmission circuit 20 is now ready for use.
You will be able to make dial signals for central office lines. In FIG. 1, the control section of the main device ME and the extension line system are omitted. The conventional circuit system has the following drawbacks.

Telephone network 21 is special.

When power is on/off, it is necessary to switch between the balanced circuit networks 31 and 32.

Since it is compensated by passive elements, the call loss is 1~
It may be possible to compensate only up to about 2dB. Therefore, it is necessary to reduce the loss in the transformers 5 and 8, and in order to reduce the communication loss at the cross point 7, where the transformer is expensive, it is necessary to increase the impedance of the communication path.

By increasing the impedance, crosstalk characteristics deteriorate.

In order to solve these drawbacks, the present invention provides an economical solution by inserting a bidirectional amplifier into the office line side link or telephone side link of the communication path configuration and compensating for call loss during power on and power outage. The present invention provides a subscriber-side telephone device designed to improve communication performance and call performance.

The present invention will be explained in detail below.

FIG. 2 is an embodiment of a block diagram of a telephone device according to the present invention, in which 1 is a main device, and 2a and 2b are telephones. These telephones are connected to n terminal telephones 2a for power outage corresponding to the number of accommodated station lines n.
m-n general terminal telephones 2b are connected. The main device 1 has a power outage switching circuit 3 and 9a,
Office line circuits 41 to 4n, input transformers 51 to 5n,
Bidirectional amplifier 6a or 6b, office line connection switch network 7, office line crosspoint switch 7a, output transformers 81 to 8m, speech current supply circuit 9b,
Sender circuit 100, extension circuit 101, extension connection switch network 102, extension cross-point switch 102a, CPU (main device control circuit) 103,
This is a DTR (data transmitting/receiving circuit) 104. The telephone set 2a consists of 20 central office line dialing circuits (PBD/DPD) for use during power outages, and 2 telephone circuit networks (TNW).
1. Contact 22a of speaker switching relay 22, speaker amplifier 23, speaker 24, DTR (data transmission/reception circuit) 25, CPU (telephone control circuit) 26,
These are a dial 27, a central office line, an extension line and function keys 28, and various status displays 29. Here, when the telephone 2a is talking using the central office line _L1 , two cases will be described: when power is on and when there is a power outage. When the power is on, the central line
In L ₁ , the power outage switching circuits 3 and 9a fall to the dotted line side,
[Station line circuit 41 → Input transformer 51 → Bidirectional amplifier 6a-1 → Applicable cross point switch 7
a → Output transformer 81 → Telephone current supply circuit 9b]
to the terminal telephone 2 via the power outage switching circuit 9a.
The circuit configuration is such that it is connected to the telephone network (TNW) 21 of a. Note that the office line dialing circuit 20 of the terminal telephone 2a for power outage is not connected when the power is on, but is inserted into the loop and connected during a power outage.
In this state, call losses occur in the input transformer 51, crosspoint switch 7a, output transformer 81, call current supply circuit 9b, etc., but in order to compensate for these losses, there is a connection between the switch network 7 and the central office line. The circuit configuration is such that a circuit 6b is inserted between the bidirectional amplifier 6a or the switch network 7 and the terminal telephone. switch network 7 and terminal telephone 2a,
When the bidirectional amplifiers 6b are inserted between the lines 2b, the number of bidirectional amplifiers 6b is required to be equal to the number of telephones, but in the case of the bidirectional amplifiers 6a, it is necessary to install only the number of bidirectional amplifiers 6b for the number of office lines.

In the event of a power outage, the office line is switched to power outage switching circuits 3 and 9a.
falls to the solid line side and connects directly to the telephone network (TNW) 2.
1, but since the standard 601 network currently used as a telephone network is installed in the terminal telephone, there is no need to switch the balanced network even if the loop is switched due to a power outage.

Next, a description will be given of the operation of making a call on the office line and responding to an incoming call on the office line when the terminal telephone 2a uses the office line 1. First, to make a call to a central office line when the power is on, the telephone 2a lifts up the handset and presses the central office line _L1 key of the key 28, and the information is sent to the telephone control circuit (CPU) 26.
The data transmission/reception circuit (DTR) 25,
Main unit control circuit (CPU) 103 through 104
The CPU 103 turns on the station line loop in the station line circuit 41 and turns on the corresponding cross point 7.
At the same time, the current supply circuit 9b is turned on, and information is sent through the data transmitting/receiving circuit (DTR) 104, 25 to display the lamp of the central office line _L1 in its own use state, and the telephone control circuit is activated based on the corresponding lamp display information. (CPU) 26 controls the lamp corresponding to station line _L1 of lamp 29. This lamp display makes it clear that the station line _L1 is in use. next,
When the dial 27 is pressed to send the central office line number, the information is sent to the telephone control circuit (CPU) 26,
is input to the main unit control circuit (CPU) 103 through the data transmission/reception circuit (DTR) 25, 104,
The main device control circuit (CPU) 103 controls the sender circuit 100 and connects the station line to the station line via the station line circuit 41.
A dialing signal (DC pulse or MF signal) is sent to _L1 , and when the dialed party responds, a telephone call can be started via the telephone loop.

To make a call to the office line during a power outage, when the telephone 2a picks up the handset and dials several digits, the dialing circuit 20 calls the office line _L1 via the power outage loop Tl.
It is possible to send a dial signal to the telephone and make telephone calls in the same way as with electricity. The dial transmission circuit 20 is designed to operate only during a power outage.

Next, we will explain the operation of responding to incoming calls on the central office line. In the case of an incoming call response on the central office line when the power is on, first, when a 16Hz ringing signal is input to the central office line _L1 , it is detected by an incoming call detection circuit (not shown) provided in the curved circuit 41,
The information is sent to the main unit control circuit (CPU) 103. The main device control circuit (CPU) 103 sends incoming call information to the extension circuit 101, and
1 turns on the crosspoint 102 corresponding to a predetermined telephone based on the information. On the other hand, CPU
The low talk current supply circuit 9 receives the incoming call information from 103.
Since a is also turned on, the incoming office ring tone (for example, electronic chime tone, etc.) is sent from the sound source circuit provided in the extension circuit 101 to the telephone 2a, etc., and
The office line _L1 lamp of the lamp 29 is set to the incoming state through the data transmitting/receiving circuits (DTR) 104, 25 and the telephone control circuit (CPU) 26, the speaker switching relay 22 is set to the inactive state, and the contact 22a is connected to the transformer 30 side to switch the speaker. An incoming call tone is sounded by a speaker 24 via an amplifier 23. Next, when you press the office line L ₁ key of the keys 28 of the telephone 2a and pick up the handset, the information is input to the main device control circuit (CPU) 103 in the same way as when making a call. ) 103 turns off the speaker switching relay 22, so the speaker stops sounding,
Put the office line L ₁ lamp in use, and as described above, turn on the office line loop in the office line circuit 41, turn on the corresponding cross point 7, turn off the cross point 102a of the incoming office ring tone, and turn on the office line loop. Enters line call mode. When responding to incoming calls on the central office line during a power outage, the central office line
When a 16 Hz ringing signal is input to _L1 , it is sent to the telephone network (TNW) 21 of the telephone 2a through the power outage switching circuits 3 and 9a, causing a power outage ringer installed in this network to ring. Next, by picking up the handset, the system enters the central office line communication state at the time of a power outage.

Next, the operation of a specific circuit example of the amplifier 6a used in the present invention will be explained with reference to FIG. This figure shows a case where a bidirectional amplifier 6a is inserted into the station line side link. 5 is an input transformer, 6a is a bidirectional amplifier, 60 and 62 are hybrid circuits, 61 and 63
is a differential amplifier, 7 is a cross point switch, 8
is the output transformer. During a call on the central office line, the impedance when disconnecting point A and looking at the central office line side is Z _A , and the impedance when disconnecting point B and looking at the telephone side is Z _B , and the values of resistors 60a and 62a are R _60a, respectively. , R _62a , the bridge equilibrium condition for these four parties R _60a :Z _A =Z ₁ :Z ₂ ,
In order to satisfy R _62a : Z _B = Z ₃ : Z ₄ ,
Ideal hybrid characteristics can be obtained by determining Z ₁ , Z ₂ , Z ₃ , and Z ₄ using a circuit as shown in b. Call loss is caused by transformers 5, 8 and crosspoint switch 7, but differential amplifier 6
This can be compensated by a gain of 1.63. Differential amplifier 6
1 is composed of an operational amplifier 61a and resistors 61b to 61e, where resistors 61b, 61d, 61
The resistance values of c and 61e are R _61b , R _61d ,
When R _61c and R _61e , R _61b ≫ _{R 60a} , R _61b = R _61d ,
When R _61c = R _61e , the gain is determined by R _61c /R _61b .

Similarly, the differential amplifier 62 is determined by the gain=R _63c /R _63b . Resistors 60a and 62a are for channel impedance matching, and the audio signal from the office line circuit passes through transformer 5, is terminated at resistor 60a, is amplified by differential amplifier 61, and is connected to resistor 62a, crosspoint switch 7, and transformer 8. is sent to the telephone network. Similarly, the voice signal from the telephone network passes through transformer 8 and crosspoint switch 7, is terminated at resistor 62a, is amplified by differential amplifier 63, passes through resistor 60a and transformer 5, and is sent out to the office line circuit. Due to the above-mentioned balance condition, the hybrid circuit 60 and the differential amplifier 61 prevent the output of the differential amplifier 61 from going around to the operational amplifier 63, and the output of the differential amplifier 63 from going around to the operational amplifier 61. Here, if Z _A = R _60a and Z _B = R _62a , if there is no call loss, resistors 63b and 63c
When the resistance values of R _63b and R _63c are respectively,
R _61c / R _61b = R _63c / R _63b = 2, and on the output side
Since R _62a Z _B , the amplification degree of the differential amplifiers 61 and 62 is Z _B /(R _62a + Z _B ) = 1/2 = 6 dB.
If the values of the resistors 61b, 61c, 63b, and 63c are determined to be (6+α) dB when the call loss is αdB, the call loss can be compensated for.
Call loss can be similarly compensated when the bidirectional amplifier 6b is inserted into the telephone side link.

Next, the main device control unit (CPU) 103 and data transmitting/receiving circuit (DTR) 1 used in the present invention
04, 25, the telephone control circuit (CPU) 26 will be explained in more detail with reference to FIG.

First, the data transmitting/receiving circuit (DTR) 104 will be explained. Mutual transmission of data with the main device control circuit (CPU) 103 is performed, for example, in a 4-bit or 8-bit parallel data format, and data from the main device control circuit (CPU) 103 is transferred to the bidirectional bus driver BF. Data is once stored in the shift register _SR1 through the shift register SR1, and then sent out from the shift register _SR1 through the driver _D1 and pulse transformer _T1 in synchronization with the clock pulse from the clock source CL. Data from the telephone TEL passes through pulse transformer T ₁ and driver D ₂ to shift register SR ₂
is applied to the clock source CL and is temporarily stored in the shift register _SR2 in synchronization with the clock pulse from the clock source CL. When the shift register SR ₂ becomes full of accumulated data, the shift register SR 2 shifts to the main unit control circuit (CPU) 103.
The main unit control circuit (CPU) 103 receives the data as a parallel signal. In addition, this data transmitting/receiving circuit (DTR) 1
In 04, power is supplied to the telephone TEL through a chiyoke coil CH so as to have a high impedance for data transmission pulses.

The data transmitting/receiving circuit (DTR) 25 is the same as the data transmitting/receiving circuit (DTR) 104 except for the bidirectional bus driver and shift registers SR ₁ and SR ₂ . Mutual data transmission between the telephone control circuit (CPU) 26 and the data transmitting/receiving circuit (DTR) 25 is performed in the form of serial data, and the telephone control circuit (CPU) 26 transmits data in synchronization with the data transmission time slot. As shown in Figure 6, the transmission direction is switched between the first half and the second half of one cycle to read and send data. To start transmission, a start bit is sent from the main equipment (ME), and the telephone control circuit (CPU)
26 receives this start bit and starts the first bit of transmission.
Ramp information following this start bit is received at a period corresponding to the time slot (τ). The second half of the cycle following the transmission of lamp information is
It is used for transmission from to the main device ME. First, an answer bit is sent out, followed by key information. This telephone control circuit (CPU) 26 is
During the time when the information is not being transmitted, it is monitored whether keys and dials related to each piece of information are pressed down, and when they are pressed down, they are stored as key information, and the main device (ME ) controls lamps, relays, etc. based on lamp information from

FIG. 7 shows the operation inside the control device (CPU) 103, 26 and the data transmission/reception circuit (DTR) 104,
25 operations and mutual data transmission order,
This is a flowchart showing ,,,. Since this is a summary of the previous explanation, detailed explanation will be omitted.

As explained above, a subscriber who configures multiple telephones to selectively connect to the central office line using a crosspoint switch, and in the event of a power outage, connects a specific telephone directly to the central office line without going through the crosspoint switch. The device of the present invention compensates for call loss during power on and power outage by inserting a bidirectional amplifier into the link on the office line side of the crosspoint switch or the link on the telephone side in the side device. Since the network can be used as is, it is very effective in space-division type telephone equipment, and has advantages in terms of economical effects and improved call performance.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the central office line communication path of a conventional key telephone device, FIG. 2 is a block diagram showing an embodiment of the telephone device of the present invention, and FIG. 3 is a block diagram of a bidirectional amplifier used in the present invention. A circuit diagram showing a specific example, FIG. 4 is a circuit diagram showing a configuration example of an impedance circuit used in the circuit of FIG. 3, and FIGS. 5, 6, and 7 are for explaining information transmission used in the present invention. These are a block diagram, a time chart, and a flow chart.

Claims (1)

[Claims] In a subscriber-side telephone device that selectively connects a plurality of telephones to a central office line, such as a one-button telephone device or PBX, a desired telephone among the plurality of telephones is connected to the subscriber-side telephone device. At the time of a power outage, a first telephone line connected to the central office line via one of a plurality of first communication paths each having a transformer arranged on the inlet side and the outlet side.
is configured to be able to switch from a connected state to a second connected state in which it is connected to the office line via a second communication path that does not involve a transformer, and the input of the plurality of first communication paths a cross-point switch for selectively connecting each transformer on the side and the output side; and a cross-point switch between each of the input-side transformers and the cross-point switch corresponding to the central office line, or between the cross-point switch and the output transformer. and a bidirectional amplifier inserted between the plurality of telephones so as to correspond to the plurality of telephones, and configured to compensate for the amount of call attenuation in the first connection state with respect to the second connection state. A subscriber-side telephone device characterized by: