JPS6257135B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a remote loop formation scheme.

The present invention mainly refers to data lines, and particularly refers to a system in which a loop is formed by a loop operation from an in-office device to a communication line and a line termination device within the data line. This loop is
It is formed by short-circuiting or equivalently short-circuiting a pair of 4-wire lines in the system on the subscriber side or by electrical control, and is formed from time to time for maintenance and testing within the data line. It is something. The details of this loop formation will be described later, but conventionally, when performing this type of loop formation operation, maintenance personnel had to go to the location where the line termination equipment was installed and operate it manually, which was uneconomical. At the same time, it was extremely inefficient. This becomes more obvious as the number of lines increases.

SUMMARY OF THE INVENTION In view of the above circumstances, an object of the present invention is to provide a loop forming method that is economical and efficient and can easily cope with an increase in the number of lines, and specifically, a loop forming method using remote control.

In accordance with the above object, the present invention provides a first loop forming means and a first loop forming means set in a distant line terminating device from an in-office device via a 4-wire line consisting of a pair of originating wires and a pair of destination wires. In the remote loop forming method in which two loop forming means are selectively driven, the originating direction wire pair and the destination direction wire pair are respectively injected with (positive and negative) polarity or (negative and positive) from the in-office device side. ) is characterized in that the first loop forming means or the second loop forming means is activated on the line terminating device side by superimposing a DC voltage having a polarity of .

The present invention will be explained below with reference to the drawings.

FIG. 1 is a block diagram showing an example of a data line to which the system of the present invention is applied. However, this diagram mainly depicts the loopback test system of the data line, and the subscriber side includes a data terminal equipment (DTE) 11, a modem (MOD) 12, and a loopback adapter (LBA) 13. There is a relay station within the local office area that includes these subscriber-side members. This relay station consists of a space division distribution device (SD-DF) 15 that pulls in signals for loopback testing from a transmission path 14, a loopback control test device (LBCT) 16, a remote transmission control device (RTC) 17, and a keyboard. It consists of an operation processing unit (OPE) 18 equipped with the following. On the other hand, substantially similar components are arranged on the other side via the transmission line 14''. Corresponding devices are therefore designated with the same reference numerals with a suffix '. Although not directly related, remote transmission control devices 17 and 17' perform their own data exchange.In addition, in the event of a line failure, etc., data exchange between both systems (15-18) and (15'-18') is performed. Perform a loop back test.

By the way, the system of the present invention mainly uses the return control device 16, the space division distribution device 15 (together referred to as in-office devices), and the distant loopback adapter 13 and modem 12 among the blocks shown in FIG. (These are collectively referred to as line termination equipment). These in-office devices and line termination devices are designated by reference numerals 10 and 20, respectively. However, the other party also has a similar device 10'.
and 20' are provided. Between these devices (10, 20) or (10', 20'), a so-called loop is formed via the transmission line 14 (14') during maintenance and testing, and loop 1, loop 2, loop 3, It is called loop 4 etc.
To explain this with reference to Figure 2, loop 1 loops back the test signal at L1 in the figure.
Similarly, the tests for loop 2, loop 3 and loop 4 are L2 and L3 in the figure, respectively.
and is turned back at L4. However, the present invention is applicable to loop 2 (L2) and loop 4, which form a loop with the in-office device 10.
(L4). In loop 2, the modulated signal from the transmission line 14 is demodulated in the device 20, re-modulated, and returned to the device 10, for example.
RS (Request to Send) to CD (Carrier
Detect) or RD (Receive Data)
Operations such as wrapping the data back to SD (Send Data) are performed. Further, in the loop 4, an operation is performed in which the modulated signal on the transmission path 14 is returned to the device 10 as it is (for example, measurement of transmission loss). However, the above operation is also performed between the devices (10', 20').

Conventionally, the operations of these loops 2 and 4 have been performed manually by dispatching a maintenance person to the device 20 (20'), which has been inconvenient (as described above). Therefore, in the present invention, these operations are performed remotely from the in-office device 10 (10'). In this case, it is necessary to distinguish between loop 2 and loop 4. Various methods can be considered for this separation, but the present invention proposes a method that is the simplest and cheapest and requires almost no changes to existing equipment. FIG. 3 shows an example of implementing this method. In FIG. 3, components similar to those shown in FIGS. 1 and 2 are designated with the same reference numerals. The positioning of the configuration in FIG. 3 is roughly divided into regions with reference numbers 10, 14, and 20. In addition, the transmission line 14 is the existing 4-
It is constituted by a wire line, and includes a sending direction wire pair 14-S and a destination direction wire pair 14-R. Wire pair 14-S is DC cut and
It is connected to the in-office device 10 via an AC coupling transformer 30-S. Similarly, for the line termination device 20, a transformer 40 for DC cut and AC coupling is used.
Connect via S. The same is true for the destination wire pair 14-R, and similar transformers 30-R and 40-R exist. however,
These transformers are existing ones.

Some switching means are provided within the device 20 to form the loops 2 and 4 described above. Conventionally, this was manually operated, but in order to apply the method of the present invention, it is necessary to automate this. For example, the first loop forming means forming the loop 4 is constituted by a pair of relay contacts, as indicated by reference numeral 31. On the other hand, the second loop forming means forming the loop 2 is simply indicated by the reference numeral 32. This second loop forming means 32 performs looping from CD to RS, RD to SD, etc., so its contents are somewhat complicated, and since it is not a main component of the present invention, it is simply shown as a block. In short, a logic circuit operates in response to some instruction signal (C) and performs a turn-back such as CD→RS or RD→SD.

Next, a description will be given of how to separate the first and second loop forming means 31 and 32 from the in-office device 10. For this purpose, DC power supplies 33-1 and 33-2 on the device 10 side were introduced. Each of these includes a switch circuit 34-1 and 34-2, and preferably both are linked. Now, if command IL4 to form loop 4 is issued, relay 35-1 is energized, and switch circuit 34-1, which is the relay contact, is turned on (at this time, switch circuit 34-2 is turned off). , line 36
A positive DC voltage is superimposed on the wire pair 14-S through the wire pair 14-S, while a negative DC voltage is superimposed on the wire pair 14-R through the line 36-R.

Conversely, when command IL2 to form loop 2 is issued, relay 35-2 is excited and switch circuit 35-2 is turned on (switch circuit 35-1 is turned off). Then, in the same way, wire pair 14-S is passed through lines 36-S and 36-R.
A negative polarity DC voltage is superimposed on the wire pair 14-R, and a positive polarity DC voltage is superimposed on the wire pair 14-R. in the end,
Depending on whether it is loop 2 or loop 4, the polarity of the superimposed DC voltage on the wire pair (14-S, 14-R) is reversed.

Therefore, we provided a means to distinguish between these polarities.
Depending on the determination result of this means, the first loop forming means 31 or the second loop forming means 32 is selectively driven. In the figure, the first polarity determining means 3 is composed of diodes D1, D1' and relay coil RC.
7-1 is shown, while diodes D2, D2'
A second polarity determining means 37-2 is shown, which is composed of a photocoupler PC and a photocoupler PC. However, it should be noted that these configurations are merely examples. Due to the function of the diodes included in these means 37-1, 37-2, wire pairs (14-S, 1
4-R) becomes (positive, negative) polarity,
The first polarity determining means 37-1 becomes active, the first loop forming means 31 is driven, and loop 4 (L4) is selected. Conversely, wire pair (1
4-S, 14-R) respectively (negative, positive), the second polarity determining means 37-2 becomes active, the second loop forming means 32 is driven, and the loop 2 (L2 ) is selected. The second polarity determining means 32 is configured to send an instruction signal C to the second loop forming means 32 when it becomes active. Note that in the figure, the actual test signal is represented by the reference symbol T, and is an alternating current signal. Further, as for the DC power supply, although the case where two power supplies 33-1 and 33-2 are used is illustrated, a single DC power supply may be used. However, it is necessary to add some ingenuity to the switch circuits 34-1 and 34-2, but a person skilled in the art can easily deduce an example of its implementation, so a description thereof will be omitted. In short, a double-pole, double-throw switch and a polarity changeover switch are sufficient.

As explained above, according to the present invention, a remote-controlled loop formation method is realized which is simple and inexpensive and requires almost no changes to existing equipment.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an example of a data line to which the system of the present invention is applied, FIG. 2 is a block diagram for explaining the meanings of loop 1, loop 2, loop 3, and loop 4, and FIG. FIG. 1 is a circuit diagram showing an embodiment for implementing the method of the present invention. In the figure, 10 (10') is an in-office device, 14
(14') is the transmission line, 14-S is the source wire pair,
14-R is a destination wire pair, 20 (20') is a line termination device, 31 is a first loop forming means, 32
is the second loop forming means, 33-1 and 33-2 are DC power supplies, L2 is the path of loop 2, and L4
indicates the route of loop 4.

Claims (1)

[Claims] 1 From the in-office equipment via a 4-wire line consisting of an outgoing wire pair and an incoming wire pair,
In a remote loop forming method in which a first loop forming means and a second loop forming means set in a distant line terminating device are selectively driven, a second loop forming means is provided on the line terminating device side of the 4-wire line. a first polarity determining means and a second polarity determining means;
On the other hand, a DC power supply having positive polarity and negative polarity is provided on the in-office equipment side of the 4-wire line, and the DC power supply supplies (positive and negative) signals to the outgoing direction wire pair and the incoming direction wire pair, respectively. By superimposing DC voltages of polarity or (negative and positive) polarity, the first loop forming means and the second loop forming means are formed via the first polarity determining means and the second polarity determining means, respectively. A remote loop forming method characterized in that each means is selectively driven.