JPH0217980B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a signal conversion transmission system that converts a channel-compatible monitoring signal from a digital exchange to a digital transmission path and sends the signal. Loop signals, E&M signals, FX in exchange networks
Monitoring signals of various signal formats such as signals are converted into A/B signal format of a digital transmission path and transmitted. For example, as shown in FIG. 1, supervisory signals from exchanges 1 and 11 are transmitted over a digital transmission line 10 between digital terminal stations 4 and 14 using the A/B signal system. In the figure, 2 and 12 are loop signal trunks, 3 and 13 are E&M signal trunks, 5, 6, 15, and 16 are channel units, 7 and 17 are FX units, 9 is a linking signal generator, 8, 18 is a multiplexing/demultiplexing unit, 19 is an FX adapter, and A to F are subscribers. Subscribers A and B use loop signaling, subscribers C and D
indicates the case where the E&M signaling system is applied, and the FX signaling system is applied to subscribers E and F, respectively.Subscriber E is accommodated in a configuration similar to a leased line to exchange 1, and is directly accommodated in exchange 11. It is possible to make a call to a long-distance subscriber F in the same way as a local subscriber. This FX signaling system is used in the United States. In the loop signaling method, monitoring signals such as call origination, call termination, dialing, etc. are formed by opening and closing the loop, reversing the polarity of the battery, etc., and in the E&M method,
It is similar to the SS and SR signal systems, and the monitoring signal is formed by grounding or opening the lead, a battery, etc. Further, in the FX signal system, the monitoring signal is formed by grounding, opening, etc., and also includes a linking signal. Therefore, it is not possible to perform the same processing as the loop signal system and the E&M signal system that do not include linking signals. Conversion of the digital transmission path 10 into A/B signals is performed by the channel units 5, 6, 15, 16 and the FX units 7, 17 of the digital terminal stations 4, 14, respectively. On the digital transmission line 10, for example, as shown in FIG. 2, there are 12 frames F1 to F12, each frame is composed of 24 channels CH1 to CH24, and each channel is composed of 8 bits b0 to b7. There is. Then, in the 6th frame F6, bit b7 is set to A signal corresponding to the channel, and in the 12th frame F
In step 12, a monitoring signal based on the A/B signal system is transmitted with bit b7 as a B signal corresponding to the channel. As shown in FIG. 8, even when the digital exchange 30 and the digital transmission line 10 are connected via the digital terminal unit 20, it is necessary to identify the signal system type and perform signal conversion. A digital terminal unit having the configuration shown in FIG. 3 has been proposed. In the figure, 20 is a digital terminal unit;
1 is a transmitter, 22 is a selector, 23, 24, 25
are a loop signal conversion circuit, an E&M signal conversion circuit, and an FX signal conversion circuit, respectively; 26 is a channel data storage section; 27 is a selector; 28 is an FX signal conversion circuit; and 29 is a reception section. The digital signal from the digital exchange is inserted with a supervisory signal from the transmitter 21 and sent out to the digital transmission path, and the digital signal from the digital transmission route is received by the receiver 29, the supervisory signal is extracted, and the digital signal containing audio information is sent out. The signal is transferred to a digital switch. The channel data storage section 26 has a read-only memory (ROM) or a Japan line configuration, and stores signal system types corresponding to the channels. The monitoring signal SD from the digital exchange is sent to each signal conversion circuit 2.
3 to 25, a loop pulse LP is applied to the loop signal conversion circuit 23, an E&M pulse EP is applied to the E&M signal conversion circuit 24, and the signal system type information corresponding to the channel is sequentially read from the channel data storage unit 26. , selectors 22 and 27 are controlled according to the read signal system type information. Since the loop pulse LP and the E&M pulse EP are required to be pulses with relatively high precision, they are generally generated from a pulse generator (not shown) and added to the digital terminal unit 20. For example, for loop pulse LP, 10PPS±
The waveform is 0.5PPS and the make rate is 33.3%±2%, and the loop signal conversion circuit 2 is used as a pulse with a cycle of 10ms±5ms and a make time of 33.3ms±2ms.
Added to 3. Then, when transmitting the dial pulse, the digital exchange 30 (see FIG. 8) sets bits S ₀ and S ₁ of the supervisory signal SD to "1" (second (see table), a loop pulse as a conversion monitoring signal is output from the loop signal conversion circuit 23, is applied to the transmitter 21 via the selector 22, and as explained in FIG. The signal is sent to the digital transmission line 10. Then, in the digital exchange 30, the time corresponding to the number of sent dial pulses is monitored by software processing, and bits S ₀ and S ₁ of the monitoring signal SD are set to "0" as the time corresponding to the number of sent dial pulses has elapsed.
As a result, the transmission of the loop pulse LP is stopped. In addition, the monitor signal received and extracted by the receiver 29 via the digital transmission path 10 is sent to the selector 27 by the
The monitoring signal SCN to the digital exchange 30 as it is or after signal conversion by the FX signal conversion circuit 28
will be transferred as Table 1 shows the relationship between the A/B signal system of the digital transmission line 10 and other signal systems.

【table】

[Table] Table 2 shows the relationship between the bits S ₀ and S ₁ of the supervisory signal SD from the digital exchange and each signal system, and the relationship between the bits S ₀ and S ₁ of the supervisory signal SCN to the digital exchange and each signal system. The relationship is shown in Table 3.

【table】

[Table] In the FX signal system, the monitoring signal SCN to the digital exchange requires the conditions of the monitoring signal SD from the digital exchange, so the output of the signal conversion circuit 25 is added to the signal conversion circuit 28. . FIG. 6 shows the logic circuit of the main part of the loop signal conversion circuit 23 or the E&M signal conversion circuit 24, in which bit _S0 of the supervisory signal SD from the digital exchange is added to the exclusive OR circuit EXOR, and bit S0 of the supervisory signal SD is added to the exclusive OR circuit EXOR. _S1 and the loop pulse LP or E&M pulse EP are applied to the AND circuit AND1, and the output signal of the AND circuit AND1 is applied to the exclusive OR circuit EXOR, and the output signals are sent as the A and B signals via the selector 22. and is added to the transmitter 21 (see FIG. 3). That is, as shown in Table 1, the A and B signals in the loop signal system and the E&M signal system are both "1" or "0" with respect to the supervisory signal SD.
Therefore, the output signal of the exclusive OR circuit EXOR can be used as the A and B signals. For example, as shown in Table 2, in the loop signaling system, when the loop is open, the bits of the supervisory signal SD
Since _S0 is "0" and bit _S1 of the supervisory signal SD is "0" when the dial pulse is not sent (DP not sent), the output signal of the exclusive OR circuit EXOR becomes "0" and the output signal of the exclusive OR circuit EXOR becomes "0". As shown in Table 1, both the A and B signals become "0". Also, as shown in Table 2, when the loop is closed, bit _S0 of the supervisory signal SD becomes "1", so the output signal of the exclusive OR circuit EXOR becomes "1", and the first
As shown in the table, both the A and B signals become "1". Also, as shown in Table 2, when sending dial pulses (DP sending), bit _S1 of the monitoring signal SD is “1”.
Therefore, the output signals of the AND circuit AND1 become "1" and "0" in response to the interruption of the loop pulse LP, and dial pulses can be sent out using the A and B signals. Also, in the E&M signal system, the same correspondence as mentioned above exists, and the monitoring signal from the digital exchange
Bit _S0 of SD is "0" when the M lead is grounded or open, both A and B signals are "0", and when the M lead battery is connected, it is "1", and both A and B signals are "0". 1”. Also, dial pulse sending (DP sending)
At this time, bit S ₁ becomes “1” and the AND circuit
A dial pulse will be sent out via AND1 and exclusive OR circuit EXOR. FIG. 7 shows the logic circuit of the main part of the FX signal conversion circuit 25, and the monitoring signal SD from the digital exchange
bit S ₀ and the supervisory signal to the digital exchange
The A signal of SCN is added to the AND circuit AND2, and the output signal is used as the A signal by the selector 22.
is added to the transmitter 21 (see FIG. 3) via
Sent to digital transmission path. In other words, in the FX signal system, the A signal [A (SCN)] that indicates whether the tip is grounded or not is used to send the A signal (B signal is the SD column in Table 1) to the digital transmission path. −” (not used) is different,
In the case of Tip grounding, even if bit _S0 of the monitoring signal SD is “0” when the loop is open and “1” when the loop is closed,
If the A signal is fixed to "0" and bit _S0 of the monitoring signal SD is "1" only when the tip is not grounded, then the A
This sets the signal to "1". This relationship is the first
1, 0 above and below the SD loop open of the FX signal system in the table
and 0, 0 above and below the open loop. In the conventional configuration as described above, when the signal system corresponding to the channel is changed, the contents of the channel data storage section 26 must be changed.
For example, when switching jumpers, it is necessary to perform the work without error, and even in the case of new installations, the setting of the signal system type is similarly complicated. The present invention improves the conventional drawbacks as described above, and makes the signal conversion in the digital terminal unit compatible with channels by adding a designated signal indicating the type of signal system to the monitoring signal and sending it out from the digital exchange. The purpose of this is to make it possible to easily deal with changes in the signal system, etc. Examples will be described in detail below. FIG. 4 is a block diagram of essential parts of an embodiment of the present invention, and the same reference numerals as in FIG. 3 indicate the same parts. Digital exchanges identify the signaling type for each channel, so the monitoring signal SD
When sending out a signal, a designation signal indicating the type of signal system is added by software processing. For example, as shown in FIG. 5, a designation signal of 2 bits S ₂ and S ₃ is added to the 2 bits S ₀ and S ₁ of the monitoring signal SD, and this signal is shown as SDS. Two bits S ₀ and S ₁ of the monitoring signal SD in the signal SDS applied to the digital terminal unit 20 from the digital exchange are applied to each signal conversion circuit 23, 24, 25 as in the conventional example, and are converted into designated signals. The two bits S ₂ and S ₃ are applied to selectors 22 and 27, and from the selector 22, a conversion monitoring signal by signal conversion circuits 23, 24, and 25 according to the signal system type is applied to the transmitter 21, and the selector 27 From there, the received and extracted monitoring signal is selected as it is or the monitoring signal converted by the FX signal conversion circuit 28 is selected and transferred to the digital exchange. LOOP in FIG. 5 indicates the designation of the loop signal system, and E&M and FX indicate the designation of the E&M signal system and FX signal system, respectively. When bits S ₂ and S ₃ are "1" and "1", In the embodiment of the present invention, there is no designation, but it can also be used for designation when using other signaling systems. Furthermore, if four or more types of signal systems are used, the designated signal may have a 3-bit configuration. Since the selectors 22 and 27 are controlled by designated signals, they select the output of the signal conversion circuit according to the type of signal system corresponding to the channel and add it to the transmitter 21.
For example, as explained with reference to FIG. 2, the A signal is inserted at the 7th bit of each channel in the 6th frame, and the B signal is inserted at the 7th bit of each channel in the 12th frame to provide a digital transmission path with a speed of, for example, 1.544 Mb. It will be sent out. Even when the receiver 29 receives a digital signal at a speed of 1.544 Mb, the A signal of the 7th bit of each channel of the 6th frame and the B signal of the 7th bit of each channel of the 12th frame are extracted and looped. Selector 2 when specifying signal system and E&M signal system
From 7, the A signal, B signal and 2 bits are the monitoring signal.
The signal is transferred to the digital exchange as an SCN, and if the FX signal system is specified, a signal converted by the signal conversion circuit 28 from the selector 27 is transferred to the digital exchange as a supervisory signal SCN. As explained above, the present invention provides the digital terminal unit 20 with the signal conversion circuits 23 to 25 corresponding to the signaling type of the monitoring signal SD, the selector 22, the signal insertion and sending circuit such as the transmitter 21, etc. The monitor signal SD and a specified signal indicating the type of signal system are sent out from the unit, the selectors 22 and 27 are controlled by the specified signal, and the signal conversion output signal corresponding to the type of signal system is added to the signal insertion/sending circuit and digital Since the digital switch identifies the signal system type for each channel, it is easy to add specified signals. Therefore, when changing the signal system type or installing a new one, the digital There is an advantage that no construction work is required inside the terminal unit 20.

[Brief explanation of drawings]

Figure 1 is a block diagram of a switching network connected via a digital transmission line, Figure 2 is an explanatory diagram of the frame structure of a digital signal on the digital transmission line, etc.
3 is a block diagram of the main parts of a conventional digital terminal unit, FIG. 4 is a block diagram of the main parts of the embodiment of the present invention, FIG. 5 is an explanatory diagram of the monitoring signal of the embodiment of the present invention, and FIG. The figure shows the logic circuit of the main part of the loop signal conversion circuit and the E&M signal conversion circuit.
FIG. 8 is a block diagram of the logic circuit of the main part of the FX signal conversion circuit when a digital exchange and a digital transmission line are connected by a digital terminal unit.

Claims (1)

[Claims] 1. In a method of connecting a digital terminal unit between a digital exchange and a digital transmission line and sending a monitoring signal to the digital transmission line, the digital terminal unit:
A signal conversion circuit, a selector, and a signal insertion/sending circuit are provided that correspond to the signal format type of the supervisory signal sent from the digital exchange, and the supervisory signal corresponding to each channel from the digital exchange and the signal format type of the supervisory signal are provided. Sends a specified signal indicating
The selector is controlled by the specified signal to select the monitoring signal converted by the signal conversion circuit corresponding to the signal system type, and the signal insertion/sending circuit sends out the converted monitoring signal to the digital transmission path. A signal conversion transmission method characterized by: