JPS6131678B2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a line monitoring method, more specifically,
Relates to a system for monitoring the status of lines accommodated in a time-division exchange, that is, subscriber lines, lines to a switchboard, etc., in a line corresponding part such as a subscriber circuit, and transmitting the status information via a communication channel. .

In telephone exchanges, it is necessary to monitor active lines, identify changes in their status, and send the status information to a common control unit to take appropriate action.

Conventionally, in time-division exchanges, communication channels are not used to transmit DC signals that indicate line status information, so it is necessary to provide a separate signal line for calls. It was necessary to wire signal lines according to the number of signals.

Since line monitoring is performed in the line handling section, conventional methods complicate the wiring in the line handling section, increase costs, and when the line handling section is mounted on a printed wiring board, the number of connection terminals increases. The number of connection pins increased, resulting in pin-necks and the like.

The above drawbacks of the conventional method will be explained in detail. FIG. 1 is a connection diagram of an example of a conventional system.

In the figure, ST is a telephone, SS is a state detection circuit, LD is a loop detection circuit, H is a hybrid,
A/D and D/A are AD and DA conversion circuits, respectively, and BRS and BRR are buffer registers. The voice signal from the telephone ST reaches the hybrid H via the status detection circuit SS and the loop detection circuit LD.
Furthermore, according to the encoding command ENC from the common control device CC, the AD conversion circuit A/D encodes (PCM
The signal is modulated) and stored in the buffer register BRS, and is sent to the other party via the time division switch network TDSW in response to a transmission command S sent from the common control unit CC in the time slot assigned to the line. AC signals such as PB dial signals can be sent in the same way as the audio signals described above.

The PCM-modulated audio signal from the other party passes through the time division switch network TDSW, is temporarily stored in the buffer register BRR by the reception command R sent from the common control unit CC in the time slot assigned to the line, and is further decoded. By instruction DEC
It is decoded (PCM demodulated) in the DA conversion circuit D/A, and reaches the telephone ST via the hybrid H, loop detection circuit LD, and state detection circuit SS.

Loop detection circuit LD is on-hook of telephone ST,
It monitors the off-hook state and outputs "0" to the output OL when it is on-hook (loop broken), and outputs "1" when it is off-hook (loop present).

When the telephone ST receives a call, the common control unit CC sends a ringing command RG, and the flip-flop F/F
is set, at that time the telephone ST is in the on-hook state, and the AND gate AG is connected to the loop detection circuit.
Since the output of LD is "0", the AND gate AG outputs "1", which causes the loop detection circuit LD to send the ringing signal RGS to the telephone.
Send to ST. If it responds, the loop detection circuit LD
The output becomes "1", the AND gate AG is made non-conductive and the sending of the ringing signal RGS is stopped, and the output of the loop detection circuit LD is scanned by the scanning device SCN, so that the response is sent from the scanning device SCN to the central controller CC. tell to.

When the telephone ST makes a call (off-hook), the output of the loop detection circuit LD changes from "0" to "1", and by scanning this with the scanning device SCN, the common control device CC detects the call. telephone
When dialing is performed at ST, the loop detection circuit LD detects loop breakage due to dialing.
The dialed digits are detected by scanning the output with a scanning device SCN.

To monitor the state of the telephone ST during a call, for example, when the telephone ST is a coin telephone and it is to be detected whether or not there are any inserted coins, the common control device CC sends a detection command SI. If there are any coins left in the telephone ST, the coin contacts will be closed to connect the telephone lines _l1 and l2, and if there are no coins left, the telephone line will be connected to the telephone line l1, _l2 .
Earth air is not connected to l ₁ and l ₂ . According to the detection command SI, the communication lines l ₁ and l ₂ are switched to relays, and the presence or absence of remaining coins is detected based on their operation or non-operation.
When the relay is activated (coins remaining), the state detection circuit SS outputs "0", and when the relay is not activated (no coins are inserted), it outputs "1". The output line of this status detection circuit SS, which detects status using DC signals from such lines, is connected to a special scanning device.
The presence or absence of remaining coins is detected here by the SCNS.

In this case, if the number of types of states to be detected by the telephone ST increases, the number of output lines of the state detection circuit SS must be increased accordingly.

The details of the state detection circuit SS and the loop detection circuit LD constituting the DC signal detection means are shown in FIG. 3, and will be described later.

As mentioned above, in the conventional system, a special status information output line is provided in the line corresponding part for the DC signal from the line, which has the drawbacks of complicating the wiring, increasing costs, and causing pin-necks. Ta.

Note that there is also a known method in which only the dial pulse for connection among the DC signals is transmitted through the dial phase, but this method is only useful if the subscriber has both DC dialing and PB dialing. It is not easy to apply this method to sending out DC dial pulses during a call.

The present invention eliminates the drawbacks of the above-mentioned conventional system and eliminates the special status information output line of the line corresponding section of the accommodation line in the time division switch, thereby reducing the complexity of wiring, high cost, pin-necking, etc. It is an object of the present invention to provide a line monitoring method that can also be applied when both DC dialing and PB dialing systems are used, and when dialing pulses are sent out during a call.

According to the present invention, in a time-division exchange that transmits DC information using a communication channel for transmitting voice signals, a state detection circuit and a loop A detection means for detecting a DC signal from the line including a detection circuit, a timer that is triggered by the output of the detection means and sends an output for a certain period of time, and a DC signal identification pattern that receives the output signal of the detection means
A parallel/serial conversion buffer register for converting into a PCM signal, and a selector for switching and connecting the parallel/serial conversion buffer register to a communication channel driven by the output of the timer and directed from the line to the time division switch network. and when the detection means detects a DC signal, the selector switches to combine the DC signal identification pattern and a pattern indicating line information and send the combination to the communication channel, and transmit the combination to the information receiving trunk connected to the communication channel. This can be achieved by identifying the

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

FIG. 2 is a block diagram showing the connections of one embodiment of the present invention, and the symbols in the figure indicate the same ones as in FIG. 1. Note that PSBR is a parallel-to-serial conversion buffer register, T is a timer, and SEL is a selector. FIG. 3 is a detailed connection diagram of the DC signal detection means comprised of the loop detection circuit LD and state detection circuit SS in FIG. 2, which is also suitable for the conventional method shown in FIG. be.

In Fig. 2, as in Fig. 1, the telephone ST
The audio signal from the unit reaches the hybrid H via the state detection circuit SS and the loop detection circuit LD, and then is sent to the hybrid H by the command ENC from the common control unit CC.
Encoding in AD conversion circuit A/D (PCM modulation)
is stored in the buffer register BRS,
It is sent out by the transmission command S sent from the common control device CC in the time slot assigned to the line, and is sent to the time division switch network by the selector SEL.
It is sent to the other party via TDSW. The PB dial signal is sent as an AC signal in the same way as the audio signal described above.

The PCM-modulated audio signal from the other party passes through the time division switch network TDSW, is temporarily stored in the buffer register BRR by the reception command R sent from the common control unit CC in the time slot assigned to the line, and is further decoded. By instruction DEC
It is decoded (PCM demodulated) in the DA conversion circuit D/A, and reaches the telephone ST via the hybrid H, loop detection circuit LD, and state detection circuit SS.

FIG. 3 shows an example of detailed connections between the loop detection circuit LD and the state detection circuit SS.

In Figure 3, when the telephone ST is off-hook (with a loop), the loop detection circuit LD -
48V, relay A, contact c, status detection circuit SS relay contacts', d', telephone line l ₁ , telephone ST, telephone line
l ₂ , relay contacts d ² , ² of the state detection circuit SS, AC insensible relay B of the loop detection circuit LD, a ground circuit is configured, and relays A and B operate,
Contact b switches and connects +5V (“1”) to its output OL.

If the loop of telephone ST is broken due to on-hook or dialing, etc., the circuit to relays A and B will be cut off, so relays A and B will be inoperative or will be restored, and contact b will be in the restored state, so the output will be
Connect earth air (“0”) to OL.

When the telephone ST receives a call, the common control unit CC sends a ringing command RG (“1”) to set the flip-flop F/F, and since the telephone ST is on-hook at this time, the AND gate AG activates the loop detection circuit. Since it is in a conductive state due to the output “0” of the LD, the AND gate AG outputs “1” (the second
figure). As a result, the relay C operates via the relay driver DC in the loop detection circuit LD, and the switching of the contact c causes the calling signal RGS to be transmitted via the contact c.
The call is sent to the telephone ST via the communication lines l ₁ and l ₂ and a call is made. At this time, relay B does not operate because it is not affected by alternating current. When the telephone ST responds (off-hook), a loop is formed and the circuit described above is constructed, and relay B is operated by the -48V DC superimposed on the ringing signal RGS. Due to the switching of contact b, the output OL of the loop detection circuit LD becomes "1", the AND gate AG is made non-conductive, the relay C is restored, and the transmission of the calling signal RSG is stopped by the restoration of the contact c. Then, by scanning the output "1" of the output end OL of the loop detection circuit LD with the scanning device SCN, the scanning device SCN transmits the response of the telephone ST to the common control device CC.

When the telephone ST makes a call (off-hook), the output of the loop detection circuit LD changes from "0" to "1", and by scanning this with the scanning device SCN, the common control device CC identifies that a call has been made. . When the common controller CC identifies this call, it connects the telephone ST to an information receiving trunk (an example is shown in FIG. 4) via the time division switch network TDSW.

Next, when dialing is performed on the telephone ST, the output OL of the loop detection circuit LD changes from "1" to "0" in accordance with the dial number information. This change triggers timer T (Fig. 2), and the output of timer T switches selector SEL to switch parallel/serial conversion buffer register PSBR to time division switch network.
Connect to the call channel leading to TDSW.

Timer T is set for a certain period of time after the trigger (in this case, the period is sufficient to cover the period from receiving a dial pulse to receiving the next dial pulse).
A monostable multivibrator that generates an output and can be retriggered, or a monostable multivibrator that generates an output after a trigger and maintains the output until the end of a certain counting period, and if it is triggered again during this counting period, it recovers and generates a new one. It can be composed of a counting circuit or the like that starts counting at a certain time, and continuously generates an output during a series of dial pulse trains to switch the selector SEL.

On the other hand, the dial information is branched and reaches the parallel-to-serial conversion buffer register PSBR, and is written to a specific bit position for dial information among the information bits other than the identification bits described below. This parallel-to-serial conversion buffer register PSBR has, for example, an 8-bit cell corresponding to a PCM code per time slot, and the upper 4 bits contain a certain pattern for identifying a DC signal. 4 bits are stored, and in response to a transmission command S from the common control device CC, 4 information bits, including 4 bits of identification bits and the bits in which the above dialing information is written, are sent out in series and placed on the communication channel. It is sent to the information receiving trunk via the time division switch network TDSW. That is, the dialed digit information is sent to the speech channel.

Information indicating the state of the line, for example, if the telephone ST is a coin telephone, a DC signal indicating whether there are any coins left in the telephone is sent to the information receiving trunk via the communication channel as follows.

In Figure 3, the operation command is sent from the common control device CC.
When SI ₁ (SI in Figure 2 is representative of various operation commands) is sent, relay D operates via relay driver DD, operating contacts d ¹ and d ² , and relay E is activated. Connect to the communication lines l ₁ and l ₂ . If there are any coins left in the coin telephone, the contacts operated by the remaining coins are closed and the earth air is connected to the communication lines l ₁ and l ₂ , so this earth air is connected to the communication lines l ₁ and l ₂ and the contacts.
The signal is applied to relay E via d ¹ and d ² and relay E operates. The contact e switches, and the output terminal os of the state detection circuit SS changes from output "1" (+5V) to "0" (earth). This output "0" is stored in a specific bit position for this information, which is different from the dial information bit position, among the information bits of the parallel-to-serial conversion buffer register PSBR.

Note that contacts d ¹ and d ² switch due to the operation of relay D, which causes the loop to break and the loop detection circuit to disconnect.
Loop breakage is detected in LD, and its output OL becomes "0" as described above, which causes the timer T
is given to trigger this, and its output switches the selector SEL, connects the parallel-to-serial conversion buffer register PSBR to the speech channel that reaches the time division switch network TDSW, and converts the contents of the speech channel to the time division switch network TDSW in the same manner as above. The information is then sent to the information receiving trunk.

When the telephone ST is a PB dial, the PB dial signal sent from now on passes through the same communication channel as the voice signal and reaches the information receiving trunk without passing through the parallel-to-serial conversion buffer register PSBR.

In addition, the operation command SI ₂ from the common control device CC activates the relay F, switches the connection points ¹ and ² , and reverses the current direction of the communication lines l ₁ and l ₂ , thereby causing the coins in the money telephone to flow. The storage electromagnet can be operated.

In FIG. 3, T of the hybrid H is a three-winding transformer, and BN is a balanced wire network.

Further, in the above case, when the telephone ST is a two-way subscriber telephone, the operation command SI ₂ selectively sends the ringing signal RSG to either the communication line l ₁ or l ₂ to make a desired call to one of the lines, and By grounding the telephone set, it is possible to detect ground air on the communication lines l ₁ and l ₂ as described above using the operation command SI ₁ at the time of making a call, and to identify the calling telephone based on the presence or absence of the ground air.

FIG. 4 is a connection diagram of a row of information receiving trunks. As already explained, all signals sent from the line response section are put on the communication channel, passed through the time division switch network TDSW, and are temporarily stored in the buffer register BRI of the information reception trunk, and then sent to the common control unit.
It is read out every time slot assigned to the line according to the reception command R from the CC, and is input to both the PB dial signal receiver PBREC and the DC signal receiver DC REC, which are AC signal receivers. Both receivers are equipped with a circuit that distinguishes between signals and voices, and will not operate when the content stored in the buffer register BRI is voice, and will not operate when the content stored in the buffer register BRI is a DC signal such as dialed number information or line status information. , as mentioned above, is a specific pattern indicating that the upper 4 bits of the 8 bits received in one time slot are a DC signal, and moreover, this corresponds to 1/2 cycle of the lowest frequency of the audio band, 300 Hz. By being repeatedly sent over a period of time, this is identified by the pattern identification circuit PI of the DC signal receiver DC REC, and the dial pulse receiving circuit DP REC and line status information receiving circuit S REC identify each information. Receive by extracting bit information at a specific position. The AC and DC signals detected and extracted here are transferred to the logic circuit section L, edited into a form suitable for the common control unit CC, and transmitted.

Although an example in which the present invention is implemented on a subscriber's telephone line has been described above, the present invention is not limited to this, and can be implemented on other lines, such as exchange operator lines, other special lines, trunk circuits, etc. .

In the above, of the 8 bits per time slot, 4 are used as pattern bits for DC signal identification.
We have explained the case where 2 bits out of the remaining 4 bits are used for information.
More information can be conveyed using the 4 bits of information.

Furthermore, by connecting the information receiving trunk in parallel to other trunks or line corresponding parts during a call, the information receiving trunk can detect picking or dialing pulses on the telephone during a call without providing any special means. This makes it possible to take appropriate actions such as switching the call connection of the exchange handler.

As explained above, the present invention eliminates the need for special signal lines for direct current signal transmission through lines, thereby reducing the number of wiring lines and preventing pin-necks.
This prevents the high cost of the line response section, and enables automatic switching between AC signals such as voice signals and PB dial signals, and DC signals such as dial pulses and line status signals. It is possible to accommodate a mixture of rotary telephones, and it is also possible to transmit DC signals such as dial pulses and hooking during a call.Therefore, for example, it is possible to call a telephone exchange operator during a call without providing any special means. This has the effect of facilitating control for switching connections.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the connection of an example of a conventional system, FIG. 2 is a block diagram showing the connection of an embodiment of the present invention, and FIG. 3 shows the state detection circuit of FIGS. Detailed connection diagram of loop detection circuit,
FIG. 4 is a block diagram showing an example of the connection of an information receiving trunk connected to the embodiment of FIG. 2. ST...telephone, SS...state detection circuit, LD...loop detection circuit, H...hybrid, A/D...AD conversion circuit, D/A...conversion circuit, BRS, BRR...buffer register, PSBR...parallel-serial conversion buffer Register, T...Timer, SEL...Selector, AG...And gate, F/F...Flip-flop, _l1 , _l2 ...Communication line, A, C, D, E, F...Relay, B...AC non-sensing relay, DC , DD, DF...Relay driver,
BRI...Buffer register, PB REC...PB dial signal receiver, PI...Pattern identification circuit, DP REC...
Dial pulse receiving circuit, SREC...Line status information signal receiving circuit, L...Logic circuit.

Claims (1)

[Scope of Claims] 1. In a time-division exchange that transmits DC information using a communication channel that transmits voice signals, a state detection circuit and a loop detection circuit are provided in line corresponding parts of lines accommodated in the time-division exchange. a timer that is triggered by the output of the detection means and sends an output for a certain period of time; and a timer that receives the output signal of the detection means and converts the signal into a PCM signal containing a DC signal identification pattern. and a selector for switching and connecting the parallel-to-serial conversion buffer register to a communication channel driven by the output of the timer and directed from the line to the time division switch network; When the means detects a DC signal, by switching the selector, the DC signal identification pattern and a pattern indicating line information are combined and sent to a communication channel, and identified by an information receiving trunk connected to the communication channel. A line monitoring method characterized by: