GB2275847A - Telecommunications call waiting service with recorded announcement - Google Patents

Description

2275847 "A Telecormiunications Switching System" The invention relates to

telecommunication switching system, more particularly to a switching system call wait capability.

Call waiting is a feature that is increasing offered as a service by telephone utility companies. When the call wait feature is active, a subscriber talking to a third party is normally notified by tone of an incoming call. Instead of receiving a busy signal, the incoming caller receives the usual ringback signal implying that the telephone of the call party is ringing. The incoming caller has no way of knowing of the existence of the call wait feature, and especially in small communities this can lead to unnecessary concern for the welfare of, for example, an elderly subscriber because the incoming caller may believe that the subscriber is unable to answer the telephone or is away from the home or when in fact this in not the case.

U.S. Patent No. 4,661,975 discloses an enhanced call waiting service where the call party has the capability of connecting the incoming caller to a recorded announcement station. However, this system requires intervention by the called party to send a busy tone or a recorded announcement to the new caller. once the call party as intervene in this manner, the incoming call is lost and cannot be recovered by the called party. The system described in this patent is therefore of limited usefulness.

An object of the invention is to alleviate the aforementioned disadvantages prior art.

According to the present invention there is provided a telecommunications switching system with call waiting capability comprising a main controller, peripheral controller means for connection to physical devices, and switch means for routing calls to and from the physical devices, and means for sending a ringback signal to the receive channel of an incoming call when the called party is busy and the call wait feature is active, the peripheral controller means are connected to a recorded announcement device, and means are provided for temporarily connecting said recorded announcement device to said receive channel of the incoming call upon activation of the call wait feature to advise the calling party that the called party's line is busy.

In the such a system in accordance with the invention, the calling party receives the recorded announcement followed by the normal ring back signal. The calling party then knows to continue listening until the called party terminates the current call or to call back later. If the calling party hangs up, he or she does so in the knowledge that the subscriber is not out. Unlike in the prior art, the call party can communicate with the calling party anytime by hanging up the current call or by flashing to receive the call waiting.

Preferably, the system is arranged so that a single transmit channel from the recorded announcement device can be received by multiple outgoing channels. This permits a number of users to receive the recorded massage at the same time.

The invention will now be described in more detail, by way of example only, with reference to the accompanying drawings, in which:- Fig. 1 is block diagram of a telecommunication switching system in accordance with the invention; Fig. 2 is a diagram of showing the status of the system when the call wait feature is first activated; Fig. 3 is a diagram illustrating the activation of the call wait system; Pigs. 4 and 5 illustrate the status of the system as the incoming call is retrieved by the called party; and Fig. 6 is a flow chart illustrating the operation of the system.

Referring now to Fig. 1, a standard telecommunications switching system comprises a bus 1 with a main controller 2 in overall command of the system, a read-only-memory 3, and a digital signal processor 4.

The bus 1 is also connected to a circuit switch 5 and a message switch 6, these switches in turn being connected to peripheral control devices 8 connected to respective RAMs 9 and 10. The system described so far is conventional and would readily understood by one skilled in the art. One suitable system is, for example, Mitells SX500OTM.

The peripheral control devices 7 and 8 interface with physical devices through line circuit 11. Such devices may be telephone sets 12 or, for example, trunks 13. The feature of the invention is that one the line circuit 11a, instead of being connected to a telephone set or trunk, is connected to a recorded announcement device (RAD) 14.

In normal operation in accordance with standard practice in the art, the telephone sets 12 can communicate with each other through the switch or with external circuits through trunks 13.

Call waiting capability is provided in known manner.

When incoming call arrives for party A, and party A is busy, the switch advises party A in a known manner by transmitting a tone from that line, and notifies the incoming caller by returning a ring back signal on the 5 incoming line.

In accordance with the invention, as soon the call wait feature is activated, the ring back signal is first transmitted to the calling party and the peripheral control device 8 then connects the recorded announcement device 14 to the receive channel of the incoming line to transmit thereon the pre-recorded announcement. Once the announcement has been transmitted, the system reverts to normal operation, and it continues to transmit the ringback signal until such time as the calling party hangs up or the call party terminates the current call and accepts the incoming call.

The recorded announcement device (RAD) 14 can be any device capable of recording and playing back voice messages. It can be a tape-recording, or preferably a digital storage medium capable of storing digitized messages. The RAD 14 is controlled by the subscriber through the normal feature control circuitry of the switching system. The subscriber can record any appropriate message of his or her choosing.

Figs. 2 to 5 explain more fully the mode of operation of the system.

In Fig. 2, subscribers B and C are engaged in conversation. Each party is controlled by the main controller, which transmits and receives messages on behalf of the subscribers. The main controller 2 also takes care of the handling of the RAD. When the subscriber A calls B, whose line is busy initially, the system first connects A's receive channel to the ringback generator by the circuit switch in the conventional manner. A therefore receives a ringing tone, and so far is unable to determined whether B is busy or absent. At the same time a tone is normally transmitted to B to 5 advise B of existence of the incoming call.

The system then connects the RAD 14 to A's receive channel (Fig. 3). The RAD 14 receives the request and answers in the exactly in the same manner as an ordinary subscriber telephone set so that the recorded message is transmitted through the receive channel to subscriber A. If the RAD 14 is busy, the system queues the incoming call and waits for the RAD to become free. The RAD 14 can, however, be connected to multiple channels so more then one incoming caller can receive the recorded message at the same time.

Pigs. 4 and 5 illustrate what happens when subscriber A is listening to the RAD and subscriber B wishes to retrieve the call. The subscriber B is simply connected to subscriber A through the switching system, and the RAD 14 is disconnected. This is handled by a message sent by subscriber B's process handler in the main controller to subscriber A's process handler. Subscriber A's handler then disconnects his receive path from the RAD's transmit path and connects it to B's transmit path. Subscriber A's transmit path is then connected to subscriber B's receive path, and a two-way conversation can take place.

More details of the operation of the system are shown in Figure 6. It will be seen that unlike the prior art, the system notifies the caller of the status of the line without interfering with the call waiting facility. The new caller is fully advised of the situation and has the option of holding the line to wait for the called party to become free or hanging up and trying again later, but the knowledge that the called party is present.

I- 1.

CLA_= 1. In a telecommunications switching system with call waiting capability comprising a main controller, peripheral controller means for connection to physical devices, and switch means for routing calls to and from the physical devices, and means for sending a ringback signal to the receive channel of an incoming call when the called party is busy and the call wait feature is active, the improvement wherein said peripheral controller means are connected to a recorded announcement device, and means are provided for temporarily connecting said recorded announcement device to said receive channel of the incoming call upon activation of the call wait feature to advise the calling party that the called party's line is busy.

2. A telecommunications switching system as claimed in claim 1, wherein said means for temporarily connecting said recorded announcement device to the receive channel of an incoming call permit said device to be connected simultaneously to a plurality of such channels. whereby a plurality of callers can receive the message at the same time.

3. A telecommunications switching system as claimed in claim 2, wherein said recorded announcement device comprises memory means for storing a digitized announcement and means for permitting subscriber access thereto to permit recording and storage of said announcement by the subscriber.

4. A telecormmications switching system substantially hereinbefore described with reference to the accompanying drawings.