JPS59262A - Controlling system in case of abnormal congestion of time division switchboard - Google Patents

Abstract

PURPOSE:To suppress effectively new calling from a subscriber in case of an abnormal congestion of a time division switchboard, by sending out a busy-back signal to a calling subscriber from a signal sending-out relay corresponding to a telephone set of the calling subscriber, and making him give up his calling. CONSTITUTION:When a subscriber executes off-hook of a telephone set TEL, a signal sending-out relay RL (not shown in the figure) of the subscriber's telephone set TEL is operated. As a result, a busy-back signal flows to a -48V power source through a capacitor C, a resistance r1, a switched contact rl<1>, a telephone set TEL, a circuit, a switched contact rl<0> and a resistance r2 from a busy-back signal generating device BT. In this way, the busy-back signal flows to the telephone set TEL, therefore, a busy-back tone is generated so that the subscriber gives up his calling.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention The present invention is directed to a control method when a time division switch is abnormally congested, and more specifically, to suppress new calls from subscribers when a time division switch is abnormally congested. Regarding the control method for

PRIOR ART AND PROBLEMS If a control system for suppressing new calls from subscribers during times of abnormal congestion in a time-division switching system is constructed using conventional techniques, the general approach shown in FIG. 1 will be obtained.

In Fig. 1, the terminal is the subscriber telephone, TDNW is the time-division channel device, BT is the busy signal generator, RG is the ringing signal generator, and RTP is the ring) IJ tube circuit, H is the hybrid, AID and D/A. are an AD conversion circuit and a DA conversion circuit, respectively.

The call signal sent from the telephone device is the contact point bt0゜ht.
”, reaches hybrid H via rtO, rlx,
2nd line 4#i! It is converted and reaches the A-D conversion circuit A/D,
Here, the analog speech signal is converted into a digital signal and inputted to the time division communication channel device TDNW.

On the other hand, the call signal in the form of a digital signal output from the time division communication path device T DNW is converted into an analog call signal in the D/A conversion circuit D/A, and
After that, you will reach the telephone installation.

As is well known, the high power level ringing signal is transmitted to the time division channel device TDNW, the A-D and the D-A converter A.
/D, D/A or hybrid H, the signal is sent directly to the telephone line via the contacts yzo and res of the signal sending relay RL, as shown in Fig. 1. configuration is adopted.

A signal sending relay RL (not shown) operates, and contacts rLO,
When rL' changes, the ringing signal is generated by the ringing signal generating capacity RG and the resistor r1. Switched contact rL',
Stationary contact b no 11 line, telephone equipment line, stationary contact hto, converted contact de zO
9 resistance r! The voltage flows through the 148V power supply and the telephone terminal, causing the bell to ring.

If the subscriber answers by going off-hook on the telephone device, m is connected to the above loop circuit through which the above ringing signal flows.
1 flows, and the ring trip circuit RTP detects the DC' voltage drop that occurs across the resistor r1 to cause a ring trip, that is, the relay RL is restored and stops sending out the ringing signal.

In order to suppress the subscriber from making new calls when the time-division exchange has an abnormal width, a relay BL is installed for each subscriber telephone as shown in FIG. and its contact ht0. http is inserted into the line, and the relay BL is operated for the calling subscriber,
The subscriber telephone device is connected to a busy signal generator BT.

As can be easily understood from FIG. 1, the busy signal is transmitted from the busy signal generator ET to the capacitor C1 resistor.
The switched contact ht", the line, the telephone connection, the line, the switched contact htO, flows through the resistor to the -48V power supply, and the calling subscriber hears a busy tone from the telephone connection and abandons the call. Go on-hook. In this way, new calls are suppressed.

However, this prior art has the disadvantage that it is not economical because one relay (relay tn) is required for each subscriber telephone for sending a busy signal to the subscriber telephone.

Purpose of the Invention The present invention provides a control method for suppressing new calls from subscribers when abnormal congestion occurs in a time division exchange, which eliminates the drawbacks of the prior art and is economical by saving relays compared to the prior art. The purpose is to provide a standardized method.

Embodiment of the Invention FIG. 2 is a connection diagram of an embodiment of the invention. In FIG. 2, the symbols are the same as in FIG.

When the telephone station is connected, the analog call signal sent from the telephone station is transferred from the telephone to the stationary contact point 10. It reaches hybrid H via det1, where it undergoes 2-wire and 4-wire conversion, is converted into a digital communication signal by A/D converter A/D, and is transferred to time-division communication path device TD.
Enter W. On the other hand, the digital communication signal output from the time division communication path device T DNH' is transmitted to the D-A converter D.
/A converts the signal into an analog call signal, which passes through Hybrid H and reaches the telephone station.

On the other hand, when the exchanger is in normal condition without any ringing,
A common switching relay BT (not shown) is kept inactive, and its contact bto is placed at the position shown. In this state, a ringing signal can be sent to the telephone by operating a signal sending relay RL (not shown) and switching its contacts yto and yzl.

That is, if the signal sending relay RL (not shown) is operated to switch its contacts rtO, ytl, the ringing signal generated by the ringing signal generator RG will be transferred to the stationary contact bto, unlike the ringing signal generator RG.
, resistance 71. Switching contacts yzl9 lines, telephone equipment, lines, switching contacts de10. It flows through the resistor to the 148F power supply, and then to the telephone station, causing the bell to ring.

If the subscriber responds by going off-hook on the telephone attachment, a DC loop is established through the telephone attachment, and -4B above is established.
Direct current flows through the υ resistor r1 due to the V power supply. resistance? The DC voltage across 'l is detected by the ring trip circuit RTP, and the ring trip, that is, the relay RL is restored and the ringing signal is stopped.

Now, if this time-division exchange is in an abnormally congested state and suppresses new calls from subscribers, first operate a common switching relay ET (not shown) and switch its contact b.
Switch to.

When a subscriber goes off-hook from the telephone station, this activates the signal sending relay RL of the horizontal position of the subscriber's telephone. Then, a busy signal is transmitted from the busy signal generator ET to the switched contact bto of the capacitor C2, and the resistor r1. Switched contact rzl.

line, telephone stack, line, switched contact 1p
tO.

It flows through the resistor rl to the -48V power supply. Since a busy signal (alternating current) is transmitted to the telephone stack as described above, a busy tone is emitted, causing the subscriber to abandon the call.

Even if a busy signal flows through resistor r1 as described above, -4
DC from the 8V power supply is blocked by capacitor C, and resistor r
1, there is no voltage drop due to direct current, so the ring
Trip circuit RTP is inactive and does not restore signaling relay RL. Therefore, the contact rzo,
The rtl is switched stably and the busy signal is reliably sent to the phone store.

Note that when this time-division exchange is abnormally congested, no new calls are connected, and therefore, there is no need to send a ringing signal, so the signal sending relay RL allows the busy signal to be sent to the telephone stack without any hindrance. Can be sent. During abnormal congestion, the relay RL may be operated in advance together with the common relay BTO, regardless of whether or not a subscriber makes a call.

In the above embodiment, a dedicated busy signal generator BT was used to suppress calls, but an existing busy signal generator BT provided for subscriber circuits and trunk circuits may be used instead. It can also be used for both purposes. However, it is necessary to avoid superimposing direct currents and to take into account division loss when simultaneously supplying power to multiple telephones in parallel. If a dedicated busy signal generator is used, the splitting loss can be ignored by making its output impedance sufficiently small.

Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications can be made within the technical scope. Therefore, according to the present invention, when the time division exchange becomes abnormally congested, it is possible to easily suppress new calls by the subscriber,
In this case, it is not necessary to provide one relay for transmitting a busy signal to each subscriber's telephone in order to make the calling subscriber abandon the call, unlike in the conventional technology, and instead, it is possible to reduce the power consumption of many subscribers. It is only necessary to provide one switching relay in common to the filling machine, and therefore, compared to the conventional system, the expense for the relay is reduced, and the mounting space is also saved, which has a great economical effect.

[Brief explanation of drawings]

FIG. 1 is a connection block diagram of an example of a conventional control system for suppressing new calls during abnormal congestion in a time division switch, and FIG. 2 is a connection block diagram of an embodiment of the present invention. Location...for subscriber circuit, rnyrv...time division communication path device, BT...busy signal generator, RG...ringing signal generator, RTP...ring trip circuit, H...・Hybrid, A/D...A-D conversion circuit, D/A...D-A conversion circuit, t"l, r2...resistance, C...capacitor, rto, rzt...signal Sending relay contact, BTO...Switching relay contact Patent applicant: Fujitsu Limited

Claims (1)

[Claims] In a time division exchange, a ringing signal generator, a busy signal generator, and either a ringing signal generated from the ringing signal generator or a busy signal generated from the busy signal generator are sent to the subscriber telephone. A signal sending relay provided for each subscriber telephone to connect the ringing signal or the busy signal to the signal sending relay, and a switching relay provided commonly to many subscriber telephones to switch and connect either the ringing signal or the busy signal to the signal sending relay. When there is abnormal congestion in the time division exchange, the switching relay is operated to give a busy signal to the signal sending relay corresponding to each subscriber's telephone, and the calling subscriber is notified of the call. A control method for a time-division exchange during abnormal congestion, characterized in that a busy signal is sent from a signal sending relay corresponding to a subscriber's telephone, and the call is abandoned.