JP3498575B2 - Telephone unit with built-in DSU - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a telephone device with a built-in DSU connected to an ISDN network. [0002] In general, a DSU (Digital S) having a function of forming a user / network interface is provided on an ISDN line.
An appropriate ISDN terminal device including a digital terminal such as a personal computer and an analog terminal such as a telephone is connected via an "ervice unit". In this case, this DSU is one ISU
An interface definition point T (referred to as a T point connection function) that can connect an ISDN terminal including a DSU to the SDN line;
An interface definition point S of an ISDN terminal device connected to a terminal terminal of a DSU connected to one ISDN line.
(Referred to as an S point connection function). [0003] A conventional DSU of this kind
In many cases, a dedicated machine configuration in which the T point connection function and the S point connection function are separately provided is adopted. Therefore, when a new device is to be added to the existing configuration, a DSU already exists and two or more other DSUs cannot be connected and operated in parallel. , TA). In addition, if there is no existing configuration or a new DSU
In order to connect an SU built-in telephone device, a device including the specified point T is required. As described above, in the conventional connection configuration, it is necessary to select and configure a model suitable for the use state from two or more types of dedicated machines. In order to share the two types of connection functions, expensive pulse transformers are individually assigned to the two types of transmission paths.
There are disadvantages that two sets of pulse transformers, each set including two sets, are required, which increases the cost. An object of the present invention is to share a set of two pulse transformers for the T point connection function and the S point connection function, and to easily perform the T point connection function and the S point connection function. An object of the present invention is to provide a telephone device with a built-in DSU that can be switched. In order to achieve this object, a telephone apparatus with a built-in DSU according to the present invention comprises a digital line terminal connected to an ISDN network and a digital line terminal connected to the digital line terminal. The digital circuit is transmitted from the ISDN network.
Includes a power supply detection circuit for detecting the power supply to the line termination device, the first terminal pair, the second pair of terminals and a third terminal pair, first
Terminal pair is connected to the I
An SDN network, a bidirectional common connection path is formed between the first terminal pair and the second and third terminal pairs when the power supply detection circuit detects the power supply, and the power supply detection circuit When the power supply is not detected , a bidirectional connection path is formed between the second and third terminals, and the first terminal pair is disconnected from the bidirectional connection path. And an I interface circuit connected to the second terminal pair, and a driver / receiver having the input terminal of the driver and the output terminal of the receiver connected to the third terminal pair, respectively. , The output terminal of the driver / receiver and the input terminal of the receiver, respectively.
Two pulse transformer primary side connected to the T / S point connector with a T point terminal pair and the point S terminal pair, the two
A switching switch for switching the mutual individual connection relationship between the secondary side of each of the pulse transformers and the T point terminal pair and the S point terminal pair of the T / S point connector. are doing. [0006] That is, according to the present invention, a DSU connected to an ISDN network is built in a telephone device, and the DSU,
A driver / receiver circuit for connecting the I interface circuit and the ISDN terminal device, a circuit for switching the driver / receiver for connecting the I interface circuit and an external DSU, and an external device connection point (point S And a changeover switch for changing the signal wiring at the point (T). Also, built-in DSU
And a driver / receiver circuit for connecting an ISDN terminal device to transmit and receive signals without a pulse transformer. [0007] The telephone apparatus with a built-in DSU according to the present invention has an IS
When connected to DN line, built-in D
The power supply detection circuit operates via the SU. The switching circuit operates by the operation of the detection circuit. The switching circuit is D
It is determined whether transmission / reception of information between the SU and the I interface circuit unit is to be established or not. The signal wiring at the external device connection point is switched using a manual switch according to the use of the connection form. FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention. L _1, L ₂ is an ISDN line terminals, 1 built DSU, 2 designates a feed detection circuitry, 3 or a T point interface information from the power supply detection circuit 2, if the S point interface switching circuit, 4 Is an I interface circuit connected to a high-speed digital dedicated line or a CPU, etc., and 5 is an S /
T point of the driver receiver, than two in 6 as described below
A set of pulse transformers 7 is a switch for switching transmission / reception wiring between point T and point S. 1-7
Constitutes the DSU built-in telephone device 10. When used as a T-point interface,
By connecting the ISDN lines L ₁ and L ₂ to the telephone unit 10 with a built-in DSU, power is supplied to the DSU ₁ from the network, the power supply is detected by the power supply detection circuit 2, and the result is switched to the switching circuit 3.
By notifying the, via the ISDN line L _1, L ₂
Thus , transmission / reception of information between the ISDN network and the DSU built-in telephone device 10 is established. Further, by operating the changeover switch 7 via the driver / receiver 5 and the pulse transformer 6, wiring for the T point interface is obtained. FIG. 2 is a block diagram showing a connection state of each circuit in this case.
By detecting the power supply from the DN network to the DSU 1 by the power supply detection circuit 2, the switching circuit 3 enables the first circuit on the DSU 1 side .
The second terminal pair T of the terminal pairs T ₁ and I interface 4 side
The first terminal pair of ₂ and between DSU1 side T ₁ and driver LES
Bidirectional common connection path is formed between the third terminal pair T ₃ of the receiver 5 side. As a result, the ISDN network is set to [line terminal L ₁
L ₂ ＤＳDSU1-switching circuit 3 (T ₁ , T ₂ ) ─I interface circuit 4] or a high-speed digital dedicated line or C
The connection mode I for connecting to a PU or the like and the ISDN network are set to [line terminals L ₁ , L ₃ ─ DSU1—switching circuit 3 (T ₁ , T ₃ )
The connection mode II of the T point interface connected to the T point connector via the {driver / receiver 5 {pulse transformer 6} changeover switch 7] is formed. In this case, T
A round-trip transmission path is required for the point connector as shown.
Therefore, the pulse transformer 6 is paired with two pairs to form a round trip transmission path.
Are responding. When used as an S point interface ,
By notifying the circuit 3 switches the result is judged that the feeding detection circuit 2, S point interface for feeding no from D SU1, DSU1 Between terminals T ₁ and T ₃ below
It is disconnected from the formed bidirectional common connection path . Also,
I interface circuit 4, driver / receiver 5, 2
By operating the changeover switch 7 via a pair of pulse transformers 6, the wiring for the S point interface is obtained. Figure 3 is a block diagram showing a connection state of each circuit in this case is not detected by the power supply is powered detection circuit 2 from the ISDN network to DSU1, the switching circuit 3 I interface
Face-side second terminal pair T ₂ and driver / receiver 5
Bidirectional connection path is formed between the third terminal pairs T ₃ side, connected to the line terminals L _1, L ₂ of the ISDN network DSU
The first terminal pair T ₁ of the 1 side is disconnected from the bidirectional connection path. Thereby, the connection mode III of the S point interface connected to the S point connector via [I interface circuit 4 {switching circuit 3 (T ₂ , T ₃ )} driver / receiver 5 {pulse transformer 6} switch 7] Is formed. FIGS. 4 and 5 are connection configuration diagrams of the telephone unit 10 with a built-in DSU according to the present invention. FIG. Is shown. FIG. 5 shows an example in which a DSU is provided outside and connected as an S point interface via the DSU. [0012] As described above, the present invention has two
The T point connection function and the S point connection function are shared using one set of pulse transformers, and the S / T
DSU that can easily switch points and can be realized at low cost
Since the built-in telephone device can be realized, the practical effect is extremely large.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing one embodiment of a telephone device with a built-in DSU according to the present invention. FIG. 2 shows T in the telephone apparatus with a built-in DSU according to the present invention.
It is a block diagram which shows the connection path state at the time of formation of a point interface. FIG. 3 shows S in the telephone device with a built-in DSU according to the present invention.
It is a block diagram which shows the connection path state at the time of formation of a point interface. FIG. 4 is a block diagram showing a connection example between devices when the DSU built-in telephone device according to the present invention forms a T-point interface. FIG. 5 is a block diagram showing a connection example between devices when the DSU built-in telephone device according to the present invention forms an S point interface. [Description of Signs] 1 DSU 2 Power supply detection circuit 3 Switching circuit 4 I interface circuit 5 Driver / receiver 6 Pulse transformer 7 Switching switch 10 DSU built-in telephone device 11 External DSU 12 ISDN terminal device

Continuation of front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H04M 11/00-11/10

Claims (1)

(57) Claims 1. A digital line termination device connected to an ISDN network, and connected to the digital line termination device to detect power supply from the ISDN network to the digital line termination device. A power supply detection circuit, a first terminal pair, a second terminal pair, and a third terminal pair;
The first terminal pair is connected to the ISDN network via the digital line termination device, and the first terminal pair and the second and third terminal pairs when the power supply is detected by the power supply detection circuit. second when bidirectional common connection path is formed, the detection of the feeding by said feeding detection circuit is not performed during,
A switching circuit formed between a third terminal and a bidirectional connection path, wherein the first terminal pair is separated from the bidirectional connection path; and a switching circuit connected to the second terminal pair. An interface circuit, a driver / receiver having an input terminal of a driver and an output terminal of a receiver connected to the third terminal pair, respectively, an output terminal of the driver / input terminal of the driver / receiver of the driver / receiver Connected to each primary side
Pulse transformers, a T / S point connector having a T-point terminal pair and an S-point terminal pair, the respective secondary sides of the two pulse transformers and the T
And a changeover switch for switching a mutual individual connection relationship between the T point terminal pair and the S point terminal pair of the / S point connector.