JPS5854767A - Digital telephone set - Google Patents

Abstract

PURPOSE:To decrease the number of pairs of interface lines and the power consumption, by connecting a network terminator and a digital terminal device with two sets of interface lines and a DC separation/balance-unbalancing conversion circuit. CONSTITUTION:Through the off-hook at a digital terminal device 20 at transmission, a DC voltage is given to a network terminator 19 via one set of interface line and DC separation/balancing-unbalancing conversion circuits 53, 51, a DC loop is formed between the terminator 19 and an exchange, and power supply is applied from the terminator 19 to a device 20 via another set of interface line and DC separation/balancing-unbalancing conversion circuits 52, 54, allowing to perform transmsission and calls. Further, at incoming call, the terminator 19 detects the inversion of polarity of a line voltage to form a DC loop with the exchange, and the power supply from the terminator 19 to the device 20 via the circuits 52 and 54 to attain communication.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a digital telephone device in which a network terminating device having a network terminating function and a digital terminal device having a terminal function are separately configured. This is related to the interface configuration.

Conventionally, digital telephone equipment has functions such as removing attenuation and distortion of digital pulses transmitted on subscriber lines and shaping the waveform, decomposing the transmission format of transmitted control signals and information (when receiving), A device is being considered that has a network termination function including an assembly (at the time of transmission) function, etc. together with a terminal function in an integrated structure.

FIG. 1 is a block diagram showing the circuit configuration of such a conventional digital telephone device. In the figure, 1 is a hook switch, 2 is an electronic hook switch, 3 is a polarity matching diode, 4 is a power separation/balanced unbalanced exchange circuit, 5 is a line equalization/line drive circuit, and 6 is assembly and disassembly of signals and information. circuit, 7 is a power supply circuit, 8 is a synchronization circuit, 9 is a timing signal generation circuit, 10 is an error control circuit, 11 is a signal control circuit, 1
2 is a codec (COI) EC), 13 is a communication circuit, 1
4 is a dial, 15 is a sounder, 16 is a transmitter, 17 is a receiver, 18 is a port for non-telephone information, and FSO* is a signal indicating an out-of-synchronization state.

The operation of the digital telephone device shown in FIG. 1 when making and receiving calls is as follows.

(1) When a call is made, the hook switch 1 is closed due to off-hook, a DC loop is formed with an exchange (not shown), the power supply circuit 7 of the digital telephone device is activated, and each circuit section of the digital telephone device is operated. After a synchronization establishment procedure with the exchange, signals are exchanged and a communication state is reached.

(2) When a call is received, the polarity of the line voltage is reversed on the exchange side, and the digital iNL
On the talking device side, the polarity matching diode 3 detects the polarity reversal, and a loop is formed with the exchange to connect the power supply circuit 7.
starts. The following operations are the same as when making a call.

Note that the electronic hook switch 2 is turned on when off-hook, and when disconnected, does not open the DC loop at the same time as on-hook, but is provided in order to send and receive a disconnection signal to the exchange and mutually confirm disconnection before opening the DC loop. It is something that

Regarding the digital telephone device shown in Fig. 1, it is configured separately into a network termination device with a network termination function and a digital terminal device with a terminal function, and the network interface is standardized. In addition, it may be possible to maintain network order through network termination equipment even if the terminal equipment is open to the public so that they can use whatever they like.

In this case, simply separating the conventional circuit configuration shown in FIG. 1 results in a circuit configuration as shown in FIG. 2.

In FIG. 2, 1 to 18 are the same as in FIG.
8 is the drive circuit, 22, 23, 25° 28.29.3
2 and 39 to 44 are receive circuits, but this circuit configuration has the following drawbacks.

(1) The number of interface wires is extremely large (17 are required in the example in Figure 2), which not only makes it difficult to handle in terms of installation, maintenance, and operation, but also increases costs due to cables, connectors, etc. be done. Furthermore, a large number of drive/receive circuits are required (12 sets are required in the example shown in FIG. 2), which significantly increases power consumption.

(2) If the interface line is long, the DC resistance of the interface line leading to the hook switch will be thick (this resistance will be added to the line resistance if the configuration shown in Figure 2 is used).
This results in loss of power that can be extracted by network termination equipment and digital terminal equipment.

The present invention has been made to solve these drawbacks, and therefore, an object of the present invention is to reduce the number of pairs of interface lines between the network termination device and the digital terminal device, and to reduce the power consumption. The purpose of the present invention is to provide a digital telephone device that has the following features.

The main point of the configuration of the present invention is to provide a network termination function consisting of a waveform shaping function for digital pulses transmitted on the subscriber line, and a function for disassembling and assembling the transmission format of signals and information transmitted on the subscriber line. In a digital telephone device configured by separating a network terminating device and a digital terminal device having a terminal function, two sets of ink wires each consisting of two wires are connected between the network terminating device and the digital terminal device. 7 Ace M is connected to the interface circuit through the DC separation/balanced/unbalanced conversion circuit, and when making a call, it is connected via an off-hook in the digital terminal device via a set of interface lines and the DC separation/balanced/unbalanced conversion circuit. The DC voltage is sent to the network termination device to form a DC loop between the network termination device and the switch, and the digital voltage is sent from the network termination device via another set of interface wires and a DC separation/plane/unbalanced conversion circuit. Power is supplied to the terminal device, making it possible to make and make calls (7. When receiving a call, the network termination device detects the polarity reversal of the C line voltage to form a DC loop with the exchange, and The point is that power is supplied from the network termination device to the digital terminal device via a set of interface lines and a DC separation/plane-to-unbalanced conversion circuit to enable telephone calls.

Next, an embodiment of the present invention will be described with reference to the drawings.

FIG. 3 is a block diagram showing one embodiment of the present invention. In the figure, 1-6, 8-18 are FIG.

The same thing as in FIG. 2 is shown. 45 is an electronic switch, 46 is a power supply circuit for primary stabilization of the local power supply, 47 is a power supply circuit for driving the circuit inside the network termination device, 48.57
Of the 17 interface lines shown in Figure 2, these are used to assemble (transmitting side) and disassemble (receiving side) the control signals, voice information, data information, and timing signals between the switch and the exchange that exchange signals at the logic level. interface circuit, 49
．． 56 is a receive circuit, 50.55 is a drive circuit, 5
2.53 is an interface circuit (48.57V); DC separation/balance/unbalance conversion circuit for transmitting the output signal in a balanced manner and superimposing the DC current; 51.54 is the signal sent from the conversion circuit 53.52, and A DC separation/balance/unbalance conversion circuit for separating DC current and converting a signal into an undirected signal; 58 is a power supply for obtaining the power necessary for the digital terminal device from the output voltage of the primary stabilizing power supply circuit 46; It is a circuit. Next, the operation of the circuit shown in FIG. 3 will be explained.

(1) When making a call from the digital terminal device 20.

When the hook switch 1 is closed due to off-hook, a DC voltage is applied to the electronic switch 45 through the DC separation/balanced unbalanced conversion circuit 51.53, and the electronic switch 45 is turned on. Therefore, a DC loop is formed between the exchange and the network termination device i9, and the −th order stabilizing power supply circuit 4
6 is activated, and the power supply circuit 47 is activated.

At this time, in the conventional configuration example shown in FIG. 2, the current flowing through the hook switch 1 or the electronic hook switch 2 is the total value of the current consumed by both the network termination device and the digital terminal device. In the embodiment of the present invention shown in FIG. 3, the current for starting the electronic switch 45 can be as small as the base current, so even if the line resistance of the interface line is large, the electronic switch 45 can be sufficiently turned on. can. As a result, the loss of power that can be extracted by the network termination device 19 and the digital terminal device 20 can be significantly reduced.

Further, the output of the negative-order stabilizing power supply circuit 46 is supplied to a power supply circuit 58 in the digital terminal device through DC separation/balanced/unbalanced conversion circuits 52 and 54 to supply the necessary power. Here, the interface circuits 48 and 57 assemble (transmitting side) and disassemble (receiving side) control signals exchanged with the network, information signals such as voice and data exchanged with the other terminal, and various timing signals necessary for the operation of the digital terminal device. ), so that signals can be exchanged over two wires on both the transmitting side and the receiving side, and the interface circuit 48゜57, the DC loop for driving the electronic switch, and the primary stabilizing circuit 4.
By connecting the DC output of 6 to the DC separation/plane unbalanced conversion circuits 51 to 54 as shown in FIG. 3, the network termination device 19 and the digital terminal device 20 are connected with four interface lines. This makes it possible to significantly reduce the number of interface lines, and because only two sets of drive/receive circuits are required, such as 49 and 55, and 50 and 56, power consumption can be significantly reduced.

Through the operations described above, the network terminal device and the digital terminal device are started up, and the process proceeds to dialable reception and dial origination 4 through the procedure of establishing synchronization with the exchange.

(2) When receiving a call to a digital terminal device.

When a call arrives at the digital terminal device 20, the polarity of the line voltage is reversed, thereby forming a current loop through the polarity matching diode 3 between the exchange and the network termination equipment ff19.

The following operation is equivalent to the case where a call is made from the digital terminal device 20.

Next, FIG. 4, FIG. 5, and FIG. 6 are circuit diagrams showing other configuration examples that can be used as the DC separation/balanced unbalanced conversion circuits 51 to 54 in the embodiment of FIG. The one shown in FIG. 5 can be applied to any of 51 to 54, the one shown in FIG. 5 can be applied to 52.53, and the one shown in FIG. 6 can be applied to 51.54.

FIG. 7 also shows the electronic switch 4 in the embodiment shown in FIG.
5 is a circuit diagram showing another configuration example of No. 5; FIG. In the same figure, 5
9 is a reverse current blocking diode, 60 is a relay winding, 61 is a resistor for setting the operating current of the relay, 62 is a winding 60
This is a relay contact that is controlled by the current flowing through the relay. When using the electronic switch shown in Figure 7, when the hook switch closes due to off-hook, current flows through the relay.
The relay contact 62 is closed to form a DC loop and activate the network termination device and digital terminal device.

When a call is received, a DC loop is formed by reversing the polarity, and the same function as in the embodiment shown in FIG. 3 is achieved.

As explained above, the present invention solves the drawbacks of the conventional interface configuration method that requires a large number of interface lines between the network termination device and the digital terminal device. The number of interface wires between devices can be configured with four, making it possible to significantly reduce the number of interface wires.As a result, it is possible to significantly improve installation, maintenance and operational handling, and to economize on cables, connectors, etc. In addition, regarding signal transmission and reception, the drive/receive circuit only needs 2 hours, making it possible to significantly reduce power consumption.

(2) By combining the electronic switch shown in the present invention with a DC separation/balanced/unbalanced conversion circuit, it becomes possible to separate the line resistance of the interface line from the DC loop between the exchange and the network termination device, The only causes of power loss that can be taken out by network termination devices and digital terminal devices are the minute drive current of the electronic switch and the on-resistance or the minute operating current of the relay, so that the influence on the drop in the power that can be taken out is extremely small. I can do it.

Furthermore, since power can be supplied to the network termination equipment and digital terminal equipment each time a call is made or received, there are advantages such as the ability to reduce indenter power consumption when the power is always on. have

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing the circuit configuration of a conventional digital telephone device, Fig. 2 is a block diagram showing the circuit configuration of a conventional digital telephone device when the network termination function and terminal function are separated, and Fig. 3 is a block diagram showing the circuit configuration of the conventional digital telephone device. FIG. 4, FIG. 5, and FIG. 6 are block diagrams showing one embodiment of the invention, respectively, and FIG. This figure is a circuit diagram showing another example of the configuration of the electronic switch in the embodiment of FIG. 3. Description of symbols 1...Hook switch, 2...Electronic hook switch, 3...Polarity matching diode, 4...Power separation/balance/unbalance conversion circuit, 5...Line equalization, line drive circuit, 6...Signal/information assembly/disassembly circuit, 7...
- Power supply circuit, 8... Synchronization circuit, 9... Timing generation circuit, 10... Interval control circuit, 11... Signal control circuit, 12... Codec, 13... Call circuit, 1
4... Dial, 12-11 sounder, 16... Transmitter, 17... Handset, 18... Non-telephone information boat, 19... Network termination device, 20... Digital terminal device, 21, 24, 26
゜27.30, 31, 33, 34, 35, 36, 37゜38 is a drive circuit, 22, 23, 25, 28, 29゜32.39, 40, 41.42, 43.44 is a receive circuit, 45 . . . Electronic switch, 46 . . .-order stabilization power supply circuit, 47 . . . Power supply circuit, 48 . 53, 54 are DC separation/balanced/unbalanced conversion circuits, 55...drive circuit, 56...receive circuit, 57...interface circuit, 58...
・Power supply circuit, 59...Diode, 60...Relay winding, 61...Resistor, 62...Relay contact agent Patent attorney Akio Namiki Attorney Patent attorney Kiyoshi Matsuzaki Figure 4 Fig. 5 Fig. 6 Fig. 7 Continuation of page 1 (7) Inventor Satoshi Iizuka Yokosuka Automobile 1-2356 Yokosuka Telecommunications Research Center 391-

Claims (1)

[Claims] 1) A network termination device equipped with a network termination function consisting of a waveform shaping function for digital pulses transmitted on the subscriber line and a function for disassembling and assembling the transmission format of signals and information transmitted on the subscriber line. , a digital terminal device with a terminal function, and a digital telephone device configured separately, the network termination device and the digital terminal device are connected via respective switching circuits, and when making a call, the digital terminal device Due to the off-hook at Power is supplied from the network termination device to the digital terminal device via the interface line and the DC separation/balance/unbalance conversion circuit to enable outgoing and telephone calls, and when a call is received, the network termination device detects the polarity reversal of the line voltage. In addition to forming a DC loop with the exchange, power is supplied from the network termination device to the digital terminal device via the set of interface lines and the DC separation/balanced/unbalanced conversion circuit to enable telephone calls. A digital telephone device characterized by: