WO2006079825A1

WO2006079825A1 - A telephone system and related method

Info

Publication number: WO2006079825A1
Application number: PCT/GB2006/000281
Authority: WO
Inventors: Richard Frederick Alexander Herman
Original assignee: Retell Holdings Limited
Priority date: 2005-01-29
Filing date: 2006-01-27
Publication date: 2006-08-03
Also published as: GB2437031A; GB0501939D0; GB0714606D0; GB2437031B

Abstract

In a telephone system and method of operating it, a plurality of incoming trunks are fed to a network termination point, which is connected to a private branch exchange. A plurality of branch extensions is connected to the exchange. Signals are monitored on the trunks and extensions and signals compared in order, for example, to determine which extension is using a particular trunk where two extensions are talking to each other or which extensions are on a conference call. Comparison may employ a speech detection system or algorithms such as a cancellation algorithm.

Description

A TELEPHONE SYSTEM AND RELATED METHOD

The present invention relates to a telephone system having a plurality of incoming trunks and a plurality of extensions and to a method of determining which incoming trunks is carrying the call of a selected extension or vice-versa.

Recording of calls for monitoring and training purposes is well known. In order to give more search options for searching later it is desirable to store as much information as possible about a call being monitored. It is therefore also desirable to be able to identify which incoming trunk of a plurality of incoming trunks is carrying the call of a selected extension if recording is carried out trunk side. If recording is carried out extension side, one knows the extension, but not the trunk.

According to one aspect of the present invention there is provided a telephone system having a plurality of extensions and a plurality of trunk lines and means for monitoring signals at selected points on the system and means for comparing the signals monitored.

According to another aspect of the present invention, there is provided a method of determining which points of a telephone system having a number of extensions and a number of trunk lines are carrying a call including the steps of sampling the signal at those points and comparing the signals.

According to a further aspect of the present invention there is provided a telephone system having a plurality of extensions and a plurality of trunk lines and means for monitoring the signal on a selected extension, means for monitoring the signal on each of the trunk lines, and means for comparing the extension signal monitored with the trunk line signals monitored in order to match the extension signal with a trunk signal.

According to a still further aspect of the present invention, there is provided a method of determining which extension of a telephone system having a number of extensions and a number of trunk lines is carrying the call of a selected trunk line including the steps of sampling the signal on the extension, sampling the signal sequentially on each trunk comparing the trunk signals sampled with the sampled signal on the extension and identifying when a match of signals is obtained. In a preferred embodiment of the invention, the means for monitoring the signal on a selected extension comprises a PC. Advantageously, the means for monitoring a signal on each of the trunks comprises a PC and interface card to read the data from the trunk into the PC. Preferably, the means for comparing utilises a speech detection system. In an alternative, algorithms are employed to compare signals. Preferably the algorithm is a cancellation algorithm in which one signal is inverted and added to the other signal. This system and method may also be used to determine if two extensions are talking to each other, or which are on a conference call. It may also be used to determine if an extension is on a call at all or if a signal is present because the microphone is live or a speaker is acting as a microphone when on hook.

The term telephone system includes not only conventional systems but also other systems such as voice over IP (VoIP).

In order that the invention may be more clearly understood, embodiments thereof will now be described, by way of example, with reference to the accompanying drawings in which:- Figure 1 diagrammatically illustrates the main parts of a telephone system; Figure 2 diagrammatically shows a modification of part of the system of Figure 1 modified in accordance with the invention;

Figure 3 diagrammatically shows a modification of another part of the system of Figure 1 modified in accordance with the invention;

Figure 4 graphically illustrates a monitored conversation at a selected extension of the telephone system;

Figure 5 graphically illustrates a monitored conversation on two trunk lines; Figure 6 graphically illustrates the comparison of a conversation on the extension of Figure 1 with that on three trunk lines;

Figures 7a, 7b and 7c diagrammatically show an alternative comparison method to that shown in Figures 4, 5 and 6, and

Figures 8a, 8b, 8c and 8d diagrammatically show the comparison method of Figures 7a, 7b and 7c for a no-match condition.

Referring to Figure 1 of the drawing, the telephone system comprises a network termination point 1 into which a plurality of incoming trunks 2 of the telephone company (PTT) are fed. Termination point 1 is connected to the private branch exchange (PABX) 3. Each extension of a plurality of branch extensions is connected to the exchange 3. For simplicity only one extension is shown. Each extension comprises a telephone base 4 to which a telephone handset (or headset) 5 is connected via a (curly) cord 6. On this system there are three places for the user to conveniently connect an additional piece of equipment to the system. They are between the network termination point 1 of the telephone company (PTT) and the branch exchange 3 (identified on Figure 1 as point 7); between the branch exchange 3 and the telephone base 4 (identified on Figure 1 as point 8) and between the telephone base 4 and the telephone handset (or headset) 5 (identified on Figure 1 as point 9) or at the jack plug socket therefor. Different information may be available about the call at these three different points 7, 8 and 9.

Regarding point 7, the information obtainable from an ISDN telephone trunk 3 is standard in that it is provided by the PTT (telephone company). Similar considerations apply to VoIP telephony. Normally this consists of CLI (Caller ID or Caller Line Identity) and number dialled on incoming calls and dialled number and CLI output on outgoing calls. Sometimes on incoming calls if the number dialled is a DDI (Direct Dial Inward) the call will be directed by the PABX to a particular extension to be answered but a user could use a facility of the PABX to answer the call from a different extension to that indicated by the PABX. Sometimes on outgoing calls the PABX outputs the DDI of the extension that is making a call. However if the DDI is not output, or if that extension does not have a DDI, or if the PABX is programmed to output the main switchboard number, this is not useful in determining which extension is making the call. When a telephone trunk is connected to a PABX, the PTT and the PABX allocate which call uses which channel on the line to the PTT, and so this information is not meaningful with regard to which person on which extension is making the call. When a telephone trunk is connected to a PABX, the PTT and the PABX allocate which call uses which channel on the line to the PTT, and so this information is not meaningful with regard to which person on which extension took or made the call.

Regarding point 8, the signal between the PABX and the extension (4, 5) could be analogue or digital depending upon the installation. With analogue extensions CLI or dialled number may or may not be presented by the PABX to or by the extension instrument. With digital extensions the CLI and dialled number information may be transmitted, but normally in a proprietary digital format making it decipherable only by reverse engineering of the data steam which is difficult and is manufacturer, PABX, handset (and software versions thereof) specific.

Regarding point 9, no data is available at this point, except the fact that that extension is in use.

The PABX may have a port known as an SMDR (station message detailed report) (after event) port which gives data about each call, but the data that is presented varies from PABX to PABX, and is not in real time making it very difficult to correlate information. In addition, if a call comes in to a first extension for one minute, is transferred to a second extension for one minute and is transferred to a third extension for one minute before someone hangs up, the SMDR port instead of outputting data to indicate what did actually happen may output that the first extension was on a call for one minute (and that is all), or it may output that the third extension was on a call for one minute (and that is all), or any variation and combination. Allied to the fact that the output is not in real time, it is very hard to use the extension information given to decide which call on a trunk was being handled by which extension.

The PABX may have a TAPI (Telephone Application Program Interface) port, but this also may not give all the data that would be helpful in identifying which extension is on which trunk. It may not have a TAPI port, or it may be expensive, or it may be specific to the PABX.

In addition if a caller dials a particular DDI which is answered by a different extension to that which is mapped to that DDI, then the DDI and extension information will be out of concatenation. Also a call could have begun from one extension, but could have been transferred to a different extension. The trunk information will be the same, but two or more different extensions will have been involved in the call.

From the above it can be seen that to match information that is readily available on the trunk (of CLI on inbound calls and inbound dialled number, and dialled number and output CLI on outbound calls) to which extension is making the call is not possible through existing systems.

This is a big disadvantage for requirements such as call recording, call logging, call management software and other applications for which it helps to find calls to have as much information as possible including CLI, dialled number and extension, which is, of course, a guide as to which person spoke on the call. Normally if a call recorder is connected trunk side it is possible to search for recordings by CLI and number dialled on incoming calls and dialled number and CLI output on outgoing calls but NOT by extension. Normally if a call recorder is connected handset (curly cord) side or at point 8 in diagram it is possible to search for recordings by extension, but NOT by CLI and number dialled on incoming calls and dialled number and CLI output on outgoing calls.

A first embodiment of the invention will now be described with reference to Figures 2 to 6. Figures 2 and 3 diagrammatically show part of the telephone system. In these figures, parts equivalent to parts of the system of Figure 1 bear the same reference numerals. Referring specifically to Figure 2, the curly cord 6 of the selected telephone extension is connected through a connector 10 to the sound card, USB port or any other suitable port of a PC 1 1 . A suitable connector 10 would be that sold by Retell Limited under their part number 650. Referring specifically to Figure 3, an interface 12 is connected between the branch exchange (PABX) 3 and termination point 1 and to the USB Ethernet or other suitable socket of a PC 13. PCs 1 1 and 13 may be the same PC or different PCs. This enables audio from the trunks 2 and audio from the selected extension 5 to be fed to corresponding PCs 1 1 , 13 for comparison purposes. A data output is produced by the PCs of start and stop times in the conversation being monitored by means of an appropriate computer program. Suitable software is that produced by 20/20 Speech Limited and supplied under the brand name Aurix Detector. Similar software is available from other companies.

The actual comparison will now be described with reference to Figures 4, 5 and 6 which show presence or absence of speech data plotted against time into call. This speech data is produced from the audio input to the corresponding PC 1 1 using the Aurix Detector software. Referring specifically to Figure 4, a person started talking one second into the call and stopped two seconds into the call. This might correspond to them saying "hello, John here". Then there was a pause, before someone started talking four seconds into the call, and stopped five seconds into the call. This might correspond to the other person saying "Jim here".

Referring specifically to Figure 5 the audio on the PC 13 near the trunks is converted to speech data by similar software to get the data output on the trunks 2.

In this example the data on trunk one is showing the same characteristics as the data from PC 1 1 near the extension, and so we could conclude that the extension telephone is talking on trunk one, and therefore that the CLI information on trunk one applies to the call which is on the extension.

In this case we could not know which trunk the extension was speaking on until 7 seconds into the call. Trunks could be checked to see if there is conversation. As soon as a negative result is obtained, then the system would know that the call was not on that trunk and it could be eliminated, reducing the number of trunks that have to be examined.

Even with trunks carrying conversation, trunks can be progressively eliminated from further comparison. Thus trunk three can be eliminated after one second, trunk four after three seconds and trunk two after seven seconds leaving trunk one as the only match.

When matches are obtained then the extension data for the match could be stored with the CLI and number dialled on incoming calls and dialled number and CLI output on outgoing calls enabling the searching for any of this information as part of the same search or live audio monitoring or any other use enhanced by knowing which trunk or which extension from that moment on.

An alternative system and method of matching will now be described with reference to Figures 7a, 7b, 7c, 8a, 8b, 8c and 8d. In this arrangement audio is fed to PCs or could all be done in analogue hardware from the extensions and trunks as before but standard echo cancellation algorithms or standard analogue or digital circuits or software are employed to do the matching.

An exemplary audio signal from a handset is shown in Figure 7a. if the signal from a particular trunk is the same, by inverting one of the signals and using echo cancellation algorithms the two signals would cancel each other out as shown in Figures 7a, 7b and 7c. In these figures the normal signal is shown at Figure 7a, the inserted signal at Figure 7b and the resultant signal at Figure 7c. Where signals cancel out a match between that extension and the trunk would be indicated. Where signals did not cancel out a non-match position would be indicated. Such a situation is shown in Figures 8a, 8b, 8c and 8d where an inversion of the signal shown in Figure 8a shown at Figure 8b is combined with the signal of Figure 8c to give the resultant signal of Figure 8d thus indicating no match.

The above described techniques can be used to establish if the person on one extension is talking to a person on another extension or to see if the extension is on a call.

When an extension is on a call, then the signal on the microphone/transmitter pair is the voice of the near party only. The signal on the speaker/receiver pair is that of the far party with some of the near party mixed in due to side tones. When the extension is not on a call, the phone may still be live. In this case the signal on the microphone/transmitter pair is the voice of the near party as before. However, the signal on the speaker/receiver pair may contain the near party due to side tones in the telephone instrument, but will not contain any signal from the far party. So the logic above can be used to deduce this, so that it can be said that if there is no signal from the far party on the speaker/receiver pair, even though there is a signal on that pair from the near party's side tones, no call is in progress.

Other comparisons could be used. Thus patterns in signal level, silence frequencies or distributions or any other signal characteristics could also be used.

It will be appreciated that the above embodiment has been described by way of example only and that many variations are possible without departing from the scope of the invention. For example, a connection to the trunks could be provided through an interface at point 7, and an open mike provided instead of headsets. The near party on the trunk at point 7, and the near party from the open mike may be enough to deduce which extension on which trunk.

The system could also be used to determine whether a call is in progress on a particular extension by comparing the signals at microphone and speaker. If the signals are the same, that would indicate that there is no call in progress, because if there was a call in progress then the signal at the speaker would also carry a signal from the far party as well as the signal from the near party even if the signal from the far party is in fact the long distance side tone path of the near party's signal. So even if the far party is not saying anything at the relevant time then there would still be a signal from the near party bounced back.

Claims

1 . A telephone system having a plurality of extensions and a plurality of trunk lines and means for monitoring signals at selected points on the system and means for comparing the signals monitored.

2. A telephone system having a plurality of extensions and a plurality of trunk lines and means for monitoring the signal on a selected extension, means for monitoring the signal on each of the trunk lines, and means for comparing the extension signal monitored with the trunk line signals monitored in order to match the extension signal with a trunk signal.

3. A telephone system as claimed in claim 1 or 2, in which the means for monitoring the signal on a selected extension comprises a computer.

4. A telephone system as claimed in claim 1 , 2 or 3, in which the means for monitoring the signal on each of the trunks comprises a computer and an interface card to read the data from the trunk into the computer.

5. A telephone system as claimed in claim 1 , 2, 3 or 4, in which the means for comparing utilises a speech detection system.

6. A telephone system as claimed in claim 1 , 2, 3 or 4, in which the means for comparing utilises algorithms to compare signals.

7. A telephone system as claimed in claim 6, in which the ' algorithm utilised is a cancellation algorithm in which one signal is inverted and added to the other signal.

8. A method of determining which points of a telephone system having a number of extensions and a number of trunk lines are carrying a call including the steps of sampling the signal at those points and comparing the signals.

9. A method of determining which extension of a telephone system having a number of extensions and a number of trunk lines is carrying the call of a selected trunk line including the steps of sampling the signal on the extension, sampling the signal sequentially on each trunk comparing the trunk signals sampled with the sampled signal on the extension and identifying when a match of signals is obtained.

10. A method as claimed in claim 8 or 9, in which the signals are compared by means of a speech detection system.

1 1 . A method as claimed in claim 8 or 9, in which the signals are compared utilising algorithms.

12. A method as claimed in claim 1 1 , in which a cancellation algorithm is employed in which one signal is inverted and added to the other signal.

13. A device for use in a telephone system comprising a sound receiver and a sound transmitter and means for comparing signals at the receiver and at the transmitter in order to determine if the device is in use or not.

14. A device for use in a telephone system as claimed in claim 13 in which the receiver is a microphone.

15. A device for use in a telephone system as claimed in claim 13 or

14 in which the transmitter is a loudspeaker.