JPH10276242A - Terminal equipment for communication - Google Patents

Abstract

PROBLEM TO BE SOLVED: To avoid temporary stop of operation of a data communication channel for a strap connection job and interruption of operation of a data communication channel due to strap mis-connection by eliminating the need for the strap connection job for selection of purpose of use of the communication terminal equipment. SOLUTION: A receiver side identification section 5 identifies which of R line 11 and T line 12 is a receiver side and provides an output of a receiver side identification signal 9. A selection circuit 4 based on the receiver side identification signal 9 connects the R line 11 to a reception section 2 and the T line 12 to a transmission section 3 when the R line 11 is set to the receiver side automatically or connects the T line 12 to the reception section 2 and the R line 11 to the transmission section 3 when the T line 12 is set to the receiver side. A PLL circuit 6a based on the receiver side identification signal 9 synchronizes a transmission clock signal 10 to be fed to the transmission section 3 with an in-equipment generating clock signal 8 when the T line 12 is set to the receiver side or synchronizes the transmission clock signal 10 to be fed to the transmission section 3 with an external extracted clock signal 7 when the R line 11 is set to the receiver side.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication terminal device, and more particularly, to connecting a subscriber terminal to a subscriber line, a line termination device connected to the subscriber line and a terminal connecting the subscriber terminal. Used as a device for interfacing with a data communication line between an adapter and an I interface composed of an R line and a T line, the line terminating device and the terminal adapter, and used by being connected to a line terminating device. Selection of whether to connect the receiving unit and the transmitting unit of the device to the T line or the R line of the line, respectively, depending on whether the terminal unit is used by being connected to the terminal adapter, The present invention relates to a communication terminal device that selects and switches a dependent destination of a synchronous clock of a transmission unit in response to this selection.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 2, when a subscriber terminal 24 is connected to a subscriber line and used, the subscriber terminal 24 is connected to a terminal adapter 23 and a line termination device 2.
1 and the like, an R line (downlink signal line from the subscriber line network side to the subscriber terminal side) 11 and a T line (uplink signal line from the subscriber terminal side to the subscriber line network side) 12 I composed
It is connected to the subscriber line via a data communication line conforming to the interface. At this time, the R line 11 and the T line 1 between the terminal adapter 23 and the line terminating device 21
2, terminal adapter 23 and line termination device 21
The communication terminal device shown in FIG. 3 is connected and used as a communication terminal device 22a, 22b so as to transmit and receive a signal as an interface with the communication terminal device.

The communication terminal device shown in FIG. 3 receives a reception signal from a network side of a subscriber line to a subscriber terminal 24, and transmits a signal from the subscriber terminal 24 to a network side of the subscriber line. If the transmitting unit 3 for transmitting the signal and the T line 12 are the receiving side, the transmitting clock signal 10 to be supplied to the transmitting unit 3 is synchronized with the in-device generated clock signal 8 generated inside the communication terminal device, If the R line 11 is on the receiving side, a PLL (Phase-Locked) that synchronizes a transmission clock signal supplied to the transmission unit 3 with an externally extracted clock signal 7 extracted from a reception signal received by the reception unit 2 and output. Loo
p) circuit 6b.

As shown in FIG. 2, depending on whether the communication terminal device is connected to the line terminating device 21 or the terminal adapter 23, the receiving side of the communication terminal device is connected to the T line 12 of the above line. (Communication terminal device 22)
a) or to connect to the R line 11 (for the communication terminal device 22b). Based on the selection, in the case of the communication terminal device 22a, as shown in FIG. 3, the input side of the reception unit 2 of the communication terminal device is connected to the T line 12 with the strap 25, and the output of the transmission unit 3 is output. R line 1 on the side
1 with a strap 26, and in the case of the communication terminal device 22b, in FIG.
The strap 11 is connected to the line 11, and the output side of the transmission unit 3 is connected to the T line 12 by a strap 28. In the operation of the system including the data communication line, when it is necessary to switch the use purpose between the use of the communication terminal device connected to the line terminating device 21 and the use of the terminal device connected to the terminal adapter 23, As described above, the connection of the strap connection has been changed by maintenance personnel of the system. Further, when the purpose of use of the communication terminal device is switched, the transmission clock signal 10 supplied to the transmission unit 3 of the communication terminal device is externally transmitted to the reception unit 2 of the communication terminal device. It is necessary to select whether to synchronize with an externally extracted clock signal 7 which is a clock signal extracted from a received signal received or to synchronize with an internally generated clock signal 8 which is a clock signal generated inside the apparatus. The selection of the synchronous clock is performed in the PLL circuit 6b in response to the switching of the purpose of use of the terminal device.
The selection of the synchronous clock performed in the PLL circuit 6b is also performed by changing the connection of the strap connection by maintenance personnel. When the receiving unit 2 of the communication terminal device is strap-connected to the T line 12, the communication terminal is selected. The transmission clock signal 10 supplied to the transmission unit 3 of the device is synchronized with the internally generated clock signal 8 generated inside the communication terminal device, and the receiving side of the communication terminal device is strap-connected to the R line 11. The transmission clock signal 10 supplied to the transmission unit 3 of the communication terminal device is converted into an externally extracted clock signal 7 extracted and output from a reception signal received from the outside by the reception unit 2 of the communication terminal device. Synchronized.

[0005]

In the conventional communication terminal device described above, the terminal device depends on whether the communication terminal device is used by connecting to a line terminating device or a terminal adapter. The selection of whether to connect the receiving side of the line to the T line or the R line of the above line is made by changing the connection of the strap connection by the maintenance personnel of the system. It has the disadvantage that it can be interrupted. In addition, in order to perform the above-described strap connection work for switching the purpose of use between connecting and using the communication terminal device to the line terminating device or connecting to the terminal adapter, a data communication line is used. Has the disadvantage that the operation of the data communication line must be temporarily stopped by turning off the power of the data communication device constituting the communication device.

SUMMARY OF THE INVENTION An object of the present invention is to eliminate a strap connection operation for switching the purpose of use between connecting and using a communication terminal device to a line terminating device or using a terminal adapter. An object of the present invention is to provide a communication terminal device capable of temporarily suspending operation of a data communication line for strap connection work and eliminating interruption of data communication due to an incorrect strap connection.

[0007]

According to the present invention, there is provided a communication terminal device having a receiving unit and a transmitting unit connected to a data communication line. Identifying which one is the receiving side, connecting the receiving side of the T line and the R line to the receiving unit, and connecting the transmitting side of the T line and the R line Is connected to the transmitting unit, and if the T line is a receiving side, a clock signal supplied to the transmitting unit is synchronized with a clock signal generated inside the communication terminal device, and the R line is connected to the receiving side. Then, the clock signal supplied to the transmission unit is synchronized with a clock signal extracted from the reception signal received by the reception unit.

Further, the communication terminal device of the present invention is provided between a terminal adapter to which a subscriber terminal is connected and a line termination device to which a subscriber line is connected. A transmission unit and a reception unit connected to a data communication line composed of a T line transmitting a transmission signal and an R line transmitting a reception signal from the subscriber line to the subscriber terminal; A PLL circuit for supplying a clock signal, and when the terminal is used for the terminal adapter to which the subscriber terminal is connected, the R line is connected to the receiving unit, and the subscriber line to which the subscriber line is connected is provided. When used in a data line termination device, in a communication terminal device in which the T line is connected to the receiving unit,
(A) a receiving side identification unit that identifies which of the T line and the R line is the receiving side and outputs a receiving side identification signal; (B)
A selection circuit that connects the reception unit and the transmission unit to the T line and the R line based on the reception side identification signal, wherein the PLL circuit performs the transmission based on the reception side identification signal. The clock signal supplied to the unit is synchronized with a clock signal selected from a clock signal generated inside the communication terminal device and a clock signal extracted by the receiving unit.

Further, in the communication terminal device according to the present invention, the receiving-side identifying unit detects which of the T-line and the R-line the received signal is transmitted to, and detects the T-line and the R-line. It is characterized by identifying which of the lines is the receiving side.

In the communication terminal device according to the present invention, the selection circuit may connect the T line to the receiving unit based on the receiving side identification signal if the T line is a receiving side, and
If the line is a receiving side, the R line is connected to the receiving unit.

[0011] Further, the communication terminal device of the present invention is characterized in that:
The LL circuit synchronizes a clock signal supplied to the transmission unit with a clock signal generated inside the communication terminal device if the T line is the reception side, based on the reception side identification signal, If the R line is the receiving side, the clock signal supplied to the transmitting unit is synchronized with the clock signal extracted from the received signal received by the receiving unit.

Further, the communication terminal device of the present invention is characterized in that the data communication line is a data communication line conforming to an I interface.

[0013]

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

FIG. 1 is a block diagram showing an embodiment of a communication terminal device according to the present invention.

The communication terminal device of the present embodiment shown in FIG. 1 has a receiving unit 2 and a transmitting unit 3 which are the same as the conventional communication terminal device shown in FIG. Reception side identification which detects which of the R line 11 and the T line 12 the reception signal is being transmitted, identifies which one of the R line 11 and the T line 12 is the reception side, and outputs the reception side identification signal 9 Based on the unit 5 and the receiving side identification signal 9, if the R line 11 is the receiving side, the R line 11 is connected to the receiving unit 2, the T line 12 is connected to the transmitting unit 3, and the T line 12 is connected.
Is the receiving side, the T line 12 is connected to the receiving unit 2 and the R line 11
And a selection circuit 4 for connecting the reception side to the transmission section 3 and a reception side identification signal 9
When the T-line 12 is the receiving side, the transmitting clock signal 10 to be supplied to the transmitting unit 3 is automatically generated based on the receiving-side identification signal 9 and generated in the communication terminal device. Synchronize with the clock signal 8 and, if the R line 11 is on the reception side, synchronize the transmission clock signal supplied to the transmission unit 3 with the externally extracted clock signal 7 extracted and output from the reception signal received by the reception unit 2. And a PLL circuit 6a. Note that the PLL circuit 6 a
3 in that the clock signal for synchronizing the transmission clock signal 10 is automatically selected from the internally generated clock signal 8 and the externally extracted clock signal 7 based on the receiving-side identification signal 9 output from FIG. Is different from the PLL circuit 6b of the conventional communication terminal device shown in FIG.

Next, the operation of the communication terminal device shown in FIG. 1 will be described.

In FIG. 1, the receiving side identification unit 5 is an R line 11
And the T line 12, and detects which of the R line 11 and the T line 12 the received signal is transmitted to, and determines which of the R line 11 and the T line 12 is the receiving side. A selection circuit 4 for automatically identifying and receiving a reception side identification signal 9 for notifying which of the R line 11 and the T line 12 is the reception side.
And output to the PLL circuit 6a. When the selection circuit 4 detects that the R line 11 is the reception side based on the reception side identification signal 9 output from the reception side identification unit 5, the selection circuit 4 sends the R line 11 to the reception unit 2 and the T line 12 Is automatically connected to the transmitting unit 3, and when it is detected that the T line 12 is on the receiving side, the T line 12 is automatically connected to the receiving unit 2 and the R line 11 is automatically connected to the transmitting unit 3. The PLL circuit 6a receives the reception-side identification signal 9 output from the reception-side identification unit 5, and when it is detected based on the reception-side identification signal 9 that the T line 12 is the reception side, the transmission unit 3 The transmission clock signal 10 supplied to the communication terminal is automatically synchronized with the internally generated clock signal 8 generated inside the communication terminal device, and when it is detected that the R line 11 is on the receiving side, the transmission clock signal 10 is supplied to the transmission unit 3. The transmission clock signal to be extracted is automatically synchronized with the externally extracted clock signal 7 extracted and output from the reception signal received by the reception unit 2.

As described above, the communication terminal device shown in FIG. 1 provided with the receiving unit and the transmitting unit for the data communication line conforming to the I-interface, as shown in FIG. When connecting to the line, it is automatically identified which of the R line 11 and the T line 12 of the data communication line connected to the communication terminal devices 22a and 22b is the receiving side. The receiving side of the T line 12 is automatically connected to the receiving unit 2, and the transmitting side of the R line 11 and the T line 12 is automatically connected to the transmitting unit 3. That is, the communication terminal device shown in FIG.
As shown in FIG. 2, when the terminal adapter 23 is used as the communication terminal device 22b, the R line 11 is automatically connected to the receiving unit 2 because the R line 11 is the receiving side.
The T line 12 is automatically connected to the transmitting unit 3. However, when the communication terminal device shown in FIG. 1 is used as the communication terminal device 22a on the line terminating device 21, the T line 12 is connected to the receiving side. Therefore, the T line 12 is automatically connected to the receiving unit 2 and the R line 11 is automatically connected to the transmitting unit 3.

If the T line 12 is on the receiving side, the transmitting unit 3
Is automatically synchronized with the internally generated clock signal 8 generated inside the communication terminal device, and the transmission clock signal supplied to the transmission unit 3 if the R line 11 is the receiving side. The signal 10 can be automatically synchronized with the externally extracted clock signal 7 extracted from the reception signal received by the reception unit 2. That is, when the communication terminal device shown in FIG. 1 is used as the communication terminal device 22a on the line terminating device 21 side shown in FIG. 2, since the T line 12 is the receiving side, it is supplied to the transmitting unit 3. Transmission clock signal 1
0 is automatically synchronized with the internally generated clock signal 8 generated inside the communication terminal device 22a, and the communication terminal device shown in FIG. 1 is used on the terminal adapter 23 side as the communication terminal device 22b. Is the transmission clock signal 10 supplied to the transmission unit 3 because the R line 11 is on the reception side.
Is automatically synchronized with the externally extracted clock signal 7 extracted from the received signal received by the receiver 2.

[0020]

As described above, the communication terminal device of the present invention detects whether the received signal is being transmitted to the R line or the T line of the data communication line, and detects the R line and the T line. A receiving side identification unit for identifying which one is the receiving side and outputting a receiving side identification signal, and based on the receiving side identification signal, if the R line is the receiving side, the R line is set to the receiving unit, and the T line is set to the A selection circuit that automatically connects to the transmission unit, automatically connects the T line to the reception unit if the T line is the reception side, and automatically connects the R line to the transmission unit;
Based on the receiving side identification signal, if the T line is the receiving side, the transmission clock signal to be supplied to the transmitting unit is automatically synchronized with the clock signal generated in the apparatus, and if the R line is the receiving side, the transmitting clock signal is supplied to the transmitting unit. A PLL circuit for automatically synchronizing a transmission clock signal with an externally extracted clock signal extracted and output from a reception signal received by the reception unit, so that the communication terminal device is connected to the line termination device for use. Eliminates the need for strap connection work to switch the purpose of use, or to connect to a terminal adapter, and suspends data communication line operation for strap connection work, and data due to incorrect strap connection. This has the effect that communication interruption can be eliminated.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of a communication terminal device of the present invention.

FIG. 2 is an explanatory diagram showing a state of device connection when a subscriber terminal is connected to a subscriber line.

FIG. 3 is a block diagram showing a configuration of a conventional communication terminal device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Communication terminal device 2 Receiving part 3 Transmitting part 4 Selection circuit 5 Receiving side discriminating part 6 PLL circuit 7 External extraction clock signal 8 In-device generated clock signal 9 Receiving side discriminating signal 10 Transmission clock signal 11 R line 12 T line

Claims (6)

[Claims] 1. A communication terminal device comprising a receiving unit and a transmitting unit connected to a data communication line, the communication terminal device comprising:
Identifying which of the line and the R line is the receiving side, connecting the receiving side of the T line and the R line to the receiving unit, and connecting the T line and the R line to each other. The transmitting side is connected to the transmitting section, and if the T line is the receiving side, a clock signal supplied to the transmitting section is synchronized with a clock signal generated inside the communication terminal apparatus, The R
If the line is a receiving side, the communication terminal device synchronizes a clock signal supplied to the transmitting unit with a clock signal extracted from a received signal received by the receiving unit. 2. A T line between a terminal adapter to which a subscriber terminal is connected and a line termination device to which a subscriber line is connected, for transmitting a transmission signal from the subscriber terminal to the subscriber line, and a T line. A transmission unit and a reception unit connected to a data communication line composed of an R line for transmitting a reception signal from a subscriber line to the subscriber terminal; and a PLL circuit for supplying a synchronous clock signal to the transmission unit. When the terminal is used for the terminal adapter to which the subscriber terminal is connected, when the R line is connected to the receiving unit, and when the terminal is used for the home data line termination device to which the subscriber line is connected. Is a communication terminal device in which the T line is connected to the receiving unit, wherein: (A) a receiving side identifying unit for identifying which of the T line and the R line is a receiving side and outputting a receiving side identification signal; , (B) before A selection circuit that connects the reception unit and the transmission unit to the T line and the R line based on the reception-side identification signal, wherein the PLL circuit performs the transmission based on the reception-side identification signal. A communication terminal device for synchronizing a clock signal supplied to a communication unit with a clock signal selected from a clock signal generated inside the communication terminal device and a clock signal extracted by the reception unit. . 3. The communication terminal device according to claim 2, wherein the receiving side identification unit detects which of the T line and the R line the received signal is being transmitted to and receives the T line. And a communication terminal device for identifying which of the R line and the R line is the receiving side. 4. The communication terminal device according to claim 2, wherein the selection circuit is configured to:
If the T line is a receiving side, the T line is connected to the receiving unit, and if the R line is a receiving side, the R line is connected to the receiving unit. 5. The communication terminal device according to claim 2, wherein the PLL circuit outputs a clock signal supplied to the transmitting unit if the T line is a receiving side, based on the receiving side identification signal. Synchronizing with a clock signal generated inside the communication terminal device, if the R line is a receiving side, a clock signal supplied to the transmitting unit is a clock signal extracted from a received signal received by the receiving unit. A communication terminal device for synchronizing with a communication terminal. 6. The communication terminal device according to claim 1, wherein said data communication line is a data communication line conforming to an I interface. Characteristic communication terminal device.