GB2311909A

GB2311909A - A telephone exchange providing a message waiting indicator in the form of a ringing signal

Info

Publication number: GB2311909A
Application number: GB9706691A
Authority: GB
Inventors: Hong-Myung Kim
Original assignee: Samsung Electronics Co Ltd
Current assignee: Samsung Electronics Co Ltd
Priority date: 1996-04-02
Filing date: 1997-04-02
Publication date: 1997-10-08
Also published as: DE19712567A1; CN1166742A; KR0168801B1; GB9706691D0; KR970072888A

Description

1 2311909 TELEPHONE SYSTEM INDICATING MESSAGE WAITING STATUS BACErzEOUND

OF THE IMMENTION The present invention relates to a telephone system with a message waiting service used in association with a private branch exchange system and in particular to a telephone exchange apparatus which indicates a call status if a telephone call has been made in the absence of the called subscriber and its method of operation.

Private branch exchange systems, for example, a key phone exchange system, used In private business facilities such as hotels, hospitals or corporate office buildings, etc.

are usually provided with and coupled to a multiplicity of attendant telephones in different rooms or locations. Thus, a guest or subscriber is provided with a diversity of telephone services as a called party or a calling party. Private branch exchange systems have in recent years been devised which provide an individual user with a so-called femessagewaiting service" by which the user or subscriber is automatically informed of any call made to his telephone in his absence. For such a message-waiting service, a light indicator is often provided on the telephone which when illuminated indicates that a telephone call has been received in the user's absence.

The operation of the message-waiting service will now be described in further detail. Assuming that a person 'W' (calling party) calls a person "B" (called party) on the telephone in a hotel, the private branch exchange system in the hotel generates a ring drive voltage to a service phone of the person "B". However, if the person "B" does not answer to the phone call after a predetermined time, the exchange system services the calling party with a voice message informing him that the called party is absent, by means of a so-called voice mailing system coupled to the exchange system itself. Person 'W' listens to the voice message and in reply, leaves his own message for person 2 "B", which message is then recorded in the voice mailing system, following which the exchange system provides an indicator the phone belonging to person "B" with a drive voltage which turns on an indicator light to inform person "B" that a voice message has been left for him by person 'W'. Therefore, person "B" is informed of the telephone call in his absence when he comes back to his room and will be able to listen to the voice message from person "A", if desired.

This kind of message waiting service can be afforded only to the aforementioned telephone which has an indicator, a so-called "message waiting telephone" (MWT). The indicator is preferably a neon lamp or a light emitting diode having the characteristic of being turned on in response to the application of a drive voltage of more than a given DC voltage level. Conventional exchange systems of this type usually provide two levels of DC voltage, for instance, a DC 120 Volt drive voltage to turn on the indicator and a DC 80 Volt, 20 Hz drive voltage to drive the ringer of the telephone.

For conventional message-waiting services, it is apparent that it is necessary to use a 120 Volt DC voltage source to drive a light indicator, which in most cases leads to more complicated power specification for the exchange system itself. Further, as the exchange system needs to use a separate path of control, different from the ring drive voltage, to provide the 120 volt DC voltage to a given telephone to turn on the indicator, this results in a more complicated construction of the exchange system due to the additional control logic required. Furthermore, in most cases, such additional control logic would make it impossible to have compatibility between an exchange system with ordinary telephones and an exchange system with MKTs.

It is therefore an object of the present invention to provide an improved telephone apparatus and method for informing a user of a telephone connected to a private 3 branch exchange system that a phone call has been made to him in his absence.

SUMMARY OF THE INVENTION

Accordingly, a telephone exchange system according to the present invention comprises means for generating a ring drive signal to a given called party in response to an incoming call or a voice message from a calling party, the ring drive signal having a different cadence if generated in response to a voice message than if generated in response to an incoming call.

The ring drive signals are preferably of the same voltage level. The exchange system may further comprise a power source for supplying a number of source voltages and means for generating a given ring drive signal voltage from the source voltages.

Preferably, the ring drive signal has a first cadence if generated in response to an incoming call from an external exchange system, a second cadence if generated in response to an incoming call from within the exchange system and a third cadence if generated in response to a voice message. The different cadences may result from different duty cycles of the ring drive signals.

The exchange system may further include a telephone apparatus having an indicator adapted to activate In response to a ring drive signal of the said different cadence. The telephone apparatus may also comprises a ringer for generating a ring in the telephone apparatus in response to a ring drive signal which is not of the said different cadence. Preferably, the ringer is disabled if the indicator is activated. For example, the ringer may be connected in parallel with the indicator.

The indicator may comprise a neon lamp or a light emitting diode.

4 Also according to the present invention, an operating method of a telephone exchange system comprises generating a ring drive signal to a given called party in response to an incoming call or a voice message from a calling party, the ring drive signal having a different cadence if generated in response to a voice message than if generated in response to an incoming call.

The method may further include receiving the ring drive signal in a telephone apparatus and activating an indicator if the ring drive signal is of the said different cadence. Preferably, the method further comprises generating a ring in the telephone apparatus if the ring drive signal is not of the said different cadence. 15 BRIEF DESCRIPTION OE THE DRAWINGS The present invention will now be described by way of example with reference to the accompanying drawings in which: 20 Fig. 1 is a block diagram illustrating a private branch exchange system with a message waiting telephone according to the present invention; Figs. 2A to 2C are timing diagrams for the various ring drive signals provided by the exchange system to the message waiting telephone in Fig. 1; and Fig. 3 is a block diagram illustrating a preferred embodiment of the message waiting telephone with an indicator.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

In Fig. 1 is illustrated a private branch exchange system 100 with a message waiting telephone (MWT) 300, which exchange system includes a power source supplier 110 for providing a set of DC voltages such as -48 Volt, -5 Volt and +5 Volt f rom an AC input power source. A ringer 120 generates a 20- Hz, 80-Volt ring drive voltage from the -48 Volt output of the power source supplier 110, which ring drive voltage is supplied to the MWT 300 via a subscriber line interface circuit (SLIC) 130 which may be connected to a plurality of the MWTs through a respective pair of telephone lines. namely, tip and ring, thereby serving as an interface between the exchange system 100 and the MWTs 300. It should be noted that the exchange system 100 is usually provided with a plurality of extended service phones inclusive of the MWTs through the SLIC 130.

A central processing unit (CPU) 140 receives a set of DC voltages such as -48 Volt, -5 Volt and +5 Volt from the power source supplier 110 and also controls all the switching operation of the exchange system as well as other operations. A trunk module controller (TMC) 150 controls input/output ports of the SLIC 130 in response to control commands from the CPU 140. An office line circuit (OLC) 160 makes a seizure of a given telephone office line under control of the CPU to form a speech loop path with an office line, thus serving as an interface between the above exchange system 100 and a public switching network of a telephone office exchange system (not shown).

The above exchange system 100 will usually include a memory unit, a switching circuit, a tone generator and a dual tone multi frequency transmitter and receiver, etc., which components however are not shown in the drawing for the sake of clarity. A voice mailing system (VMS) 200 is connected with the CPU 140, to provide recorded voice message services to a calling party in the absence of a called party.

A ring drive signal of 20 Hz, 80 Volt generated f rom the ringer 120 is changed in its cadence in dependence on the telephone line status and then delivered to the MWT 300, and the cadence changing operation is controlled by the CPU 140. If a dial tone is received in either one of the office lines of the exchange system, the CPU 140 controls the ports of the SLIC 130 by means of the TMC 150 and provides an office line ring signal with a duty cycle of 1-second ON and 2-second OFF as shown in Fig. 2A to the MWT 300. If a dial tone is received in either one of the extension lines 6 of the exchange system, the CPU 140 controls the ports of the SLIC 130 by means of the TMC 150 and provides an extension ring signal with a duty cycle of 1-second ON and 3-second OFF as shown in Fig. 2B to the MWT 300.

Furthermore, if a voice message from a calling party is received on either one of the office and extension lines of the exchange system, the CPU 140 controls selected ports of the SLIC 130 by means of the TMC 150 so as to provide a message waiting ring tone signal with a duty cycle of 1second ON and 1- second OFF as shown in Fig. 2C to the MWT 300. As a result, the exchange system 100 provides to the selected MWT 300 a corresponding one of an office line ring drive signal, an extension ring drive signal and message waiting ring drive signal. These ring signals have the same voltage level. Thus, it will be appreciated that while a conventional exchange system needs to be provided with not only a DC voltage source for supplying both the office line ring and the extension ring but also an additional DC voltage source for supplying the message waiting ring, the exchange system according to the present invention needs only a single DC voltage source capable of providing different cadences of ring signals as seen in Figs. 2A, 2B and 2C.

Fig. 3 shows a preferred embodiment of the message waiting telephone with an indicator for message waiting service applicable to the exchange system in accordance with the present invention. The message waiting telephone includes a tone ringer 310, a speech network 320, a message waiting detection/ indicator 330 and a dialler 340, wherein the tone ringer 310, the speech network 320 and the dialler 340 may be embodied with known circuit constructions, while the message waiting detection/indicator 330 is embodied according to the principles of the present invention.

The tone ringer 310 is connected to the exchange system 100 via two telephone lines, namely, the tip and ring, and is activated to generate a ring signal if the exchange system 7 provides either an of f ice iine ring or an extension ring so as to inform a given subscriber of an incoming call. For such a tone ringer, a piezo component and its driver circuit may be used, for example an MC34017 integrated chip. The speech network 320 receives a voice signal from a microphone 321 of the MWT for delivery to the exchange system 100 via the tip and ring lines and provides any voice message processed in the exchange system to a receiver or speaker 322 of the MWT. The dialler 340 converts any alphanumeric information keyed in a keypad 341 to a corresponding DTMF signal.

The message waiting detection/ indicator 330 is activated by application of a message waiting ring from the exchange system 100 so as to turn on a indicator light, for which a neon lamp or a light emitting diode may be used. As the message waiting detection/ indicator 330 is connected in parallel to the tone ringer 310, turning on of the indicator light causes the circuit of Fig. 3 to cut off the ring signal generated from the tone ringer.

In summary, The MWT 300 according to the present invention causes the tone ringer 310 to generate and deliver a ring signal to a subscriber if either an office line ring or extension ring is provided from the exchange system 100, whereas the MWT causes the message waiting detection/indicator 330 to turn on the indicator light so that the called party will be informed of the call in his absence by noticing that the indicator is turned on.

As may be apparent from the foregoing, the present invention provides an exchange system with message waiting telephones capable of generating various different cadences of ring signals with the same voltage according to the status of telephone lines.

The above operation for message waiting service according to the present invention can be carried out by using a single DC voltage source in a private branch exchange 8 system, thereby enabling simplified power specifications for the private branch exchange system. Further, the present invention provides a telephone apparatus and method capable of eliminating the necessity of an additional control logic for providing the drive voltage for turning on the light indicator of the message waiting telephone in the exchange system. Furthermore, the present invention provides the telephone apparatus and method capable of providing better compatibility between an exchange system extendable with ordinary telephones only and the improved exchange system connectable with the message waiting telephones for the message-waiting service.

9

Claims

CLAIMS:

1. A telephone exchange system comprising means for generating a ring drive signal to a given called party in response to an incoming call or a voice message from a calling party, the ring drive signal having a different cadence if generated in response to a voice message than if generated in response to an incoming call.

2. An exchange system according to claim 1 in which the ring drive signals are of the same voltage level.

3. An exchange system according to claim 1 or claim 2 further comprising a power source for supplying a number of source voltages and means for generating a given ring drive signal voltage from the source voltages.

4. An exchange system according to any preceding claim in which the ring drive signal has a first cadence if generated in response to an incoming call from an external exchange system, a second cadence if generated in response to an incoming call from within the exchange system and a third cadence if generated in response to a voice message.

5. An exchange system according to any preceding claim in which the different cadences result from different duty cycles of the ring drive signals.

6. An exchange system according to any preceding claim further Including a telephone apparatus having an indicator adapted to activate in response to a ring drive signal of the said different cadence.

7. An exchange system according to claim 6 in which the telephone apparatus comprises a ringer for generating a ring in the telephone apparatus in response to a ring drive signal which is not of the said different cadence.

8. An exchange system according to claim 7 in which the ringer is disabled if the indicator is activated.

9. An exchange system according to claim 8 in which the 5 ringer is connected in parallel with the indicator.

10. An exchange system according to any one of claims 6-9 in which the indicator comprises a neon lamp.

11. An exchange system according to any one of claims 6-9 in which the indicator comprises a light emitting diode.

12. An operating method of a telephone exchange system comprising generating a ring drive signal to a given called party in response to an incoming call or a voice message from a calling party, the ring drive signal having a different cadence if generated in response to a voice message than if generated in response to an incoming call.

13. A method according to claim 12 in which the ring drive signals are of the same voltage level.

14. A method according to claim 12 or claim 13 in which the ring drive signal has a first cadence if generated in response to an incoming call from an external exchange system, a second cadence if generated in response to an incoming call from within the exchange system and a third cadence if generated in response to a voice message.

15. A method according to any preceding claim in which the different cadences result from different duty cycles of the ring drive signals.

16. A method according to any one of claims 12-15 further including receiving the ring drive signal in a telephone apparatus and activating an indicator if the ring drive signal is of the said different cadence.

17. A method according to claim 16 further comprising generating a ring in the telephone apparatus if the ring drive signal is not of the said different cadence.

18. A telephone exchange system substantially as described 5 with reference to and/or as illustrated in the accompanying drawings.

19. An operating method of a telephone exchange system substantially as described with reference to and/or as 10 illustrated in the accompanying drawings.