GB2262683A - Dialled digit handler - Google Patents

Dialled digit handler Download PDF

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Publication number
GB2262683A
GB2262683A GB9127074A GB9127074A GB2262683A GB 2262683 A GB2262683 A GB 2262683A GB 9127074 A GB9127074 A GB 9127074A GB 9127074 A GB9127074 A GB 9127074A GB 2262683 A GB2262683 A GB 2262683A
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GB
United Kingdom
Prior art keywords
speech
encoding
means
signal
dtmf
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
GB9127074A
Other versions
GB9127074D0 (en
Inventor
James * Aspin Gordon
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
BRITISH AEROSPACE SPACE AND CO
British Aerospace Space and Communications Ltd
Original Assignee
BRITISH AEROSPACE SPACE AND CO
British Aerospace Space and Communications Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by BRITISH AEROSPACE SPACE AND CO, British Aerospace Space and Communications Ltd filed Critical BRITISH AEROSPACE SPACE AND CO
Priority to GB9127074A priority Critical patent/GB2262683A/en
Publication of GB9127074D0 publication Critical patent/GB9127074D0/en
Publication of GB2262683A publication Critical patent/GB2262683A/en
Application status is Withdrawn legal-status Critical

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Classifications

    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04WWIRELESS COMMUNICATION NETWORKS
    • H04W88/00Devices specially adapted for wireless communication networks, e.g. terminals, base stations or access point devices
    • H04W88/02Terminal devices
    • H04W88/021Terminal devices adapted for Wireless Local Loop operation

Abstract

Apparatus is provided for enabling a standard telephone handset to be used in conjunction with a digital mobile radiotelephone system. DTMF dialled signals are encoded into digital form suitable for transmission over an RF channel and regenerated at the receiving end for routing to their intended destination. Switching means (5) operated by a DTMF decoder (4) interrupts the link between a speech coder (3) and radio transmitter (6) while a dialling signal is present. <IMAGE>

Description

DIALLED DIGIT HANDLER This invention relates to radiotelephone communication systems and in particular to user interfaces for digital telephone systems.

In a conventional mobile telephony system, when digits are dialled using a handset, they are held in the user terminal until the SEND key is pressed. At this point the digits are transmitted to a base station by means of a signalling mechanism.

Without a SEND key or a method of signalling a SEND command from the hand set, this mechanism cannot operate.

In contrast, handsets for use with static, non-mobile telephone systems send digits by dual tone multi-frequency (DTMF) signalling or another mechanism (eg loop disconnect), and do not have a SEND key.

In digital mobile telephony, the "in-band" information ie speech, is converted to digital representation for transportation across the air interface. To conserve bandwidth, various techniques are used to minimise the bit rate of the digital modulation whilst preserving the recovered quality of the speech. However these techniques are optimised for the speech signal, not any DTMF signals which may be present in-band.

Thus, any DTMF signals present are likely to be sufficiently distorted by the speech coding method as to be unrecognisable by equipment at the receiving end of the telephone connection.

An object of this invention is to adapt a handset intended for use with a static telephone system so that it can operate satisfactorily when used as part of a mobile radiotelephone system.

In particular, it is an object of the invention to provide a means for transcoding a DTMF signal into a form suitable for transmission over a digital radio communications channel.

The invention provides encoding apparatus having an input for connection to a telephone hand-set and an output for connection to a radio transmitter, said apparatus comprising: speech coding means for digitally encoding an analogue speech signal; means for detecting and digitally encoding dialling signals; and switching means, controlled by the detecting and encoding means, for inhibiting transmission of speech signals while said dialling signals are present at the input.

According to a further aspect of the invention there is provided: decoding apparatus having an input for connection to a digital radio receiver and an output for connection to a telephone network, said apparatus comprising: speech decoding means for converting a digitally encoded speech signal into an analogue speech signal; encoding means for converting a digitally-encoded dialling signal into a DTMF signal; and switching means controlled by the encoding means for inhibiting transmission of analogue speech signals to the telephone network while a dialling signal is present at the input.

An embodiment of the invention will now be described, by way of example only, with reference to the drawings of which Fig 1 is a block diagram of an encoding system according to the invention; and Fig 2 is a block diagram of a decoding system according to the invention and In Fig 1 a static telephone handset 1 has an output line 2 which is connected, in parallel, to a speech coder 3 and a DTMF decoder 4. A switch 5, controlled by the output of the DTMF decoder 4 is interposed in a connection between the output of the speech coder 3 and one input to a digital radio transmitter 6. The transmitter 6 is provided with a second input which is connected to an output of the DTMF decoder. Signals can be transmitted over a radio link by an aerial 7.

The system of Fig 1 operates in the following manner.

When a sequence of numbers is dialled using the handset 1, a corresponding DTMF signal is generated on line 2. This signal is detected by the DTMF decoder 4.

The decoder 4 may be a commercially available device which translates DTMF tones into a binary equivalent.

The decoder 4 reacts to the detected DTMF signal by generating a signal which activates the switch 5. As a result, the output line of the speech coder 3 is interrupted. During this interruption, the sequence of numbers dialled is extracted from the DTMF signal by the decoder 4 and fed to the transmitter 6. The signal from the decoder 4 may take any convenient form of binary message. The digital radio transmitter 6 can transmit over speech and signalling channels and could for example take the form of a 900 MHz Time Division Multiple Access (TDMA) transmitter.

Thus the transmitter 6, via aerial 7, transmits information relating to the dialled number sequence over the air interface.

A signalling channel is used for transmitting said information and takes the form appropriate to the mobile telephone system with which it is being used. If the system in use is provided with a dedicated control channel, then this channel could, conveniently, be employed.

The signalling channel is opened by the presence of the first digit from the DTMF decoder 4.

When the transmission of dialled digits is complete, the switch 5 is closed on command of the decoder 4 and the link from speech coder 3 to transmitter 6 is resumed. Thus transmission of speech is possible (over a speech channel) by means of the radio transmitter 6 and aerial 7.

The speech coder 3 may be a commercially available device utilising a linear predictive coding algorithm.

In an alternative embodiment, the switch 5 is located in the link between the handset 1 and the speech coder 3.

In Fig 2, signals arriving over an air interface are received by an aerial 8 and a digital radio receiver 9. The receiver 9 has two outputs, one being connected to a speech decoder 10 and another being connected to a time delay module 11.

The output of the time delay module 11 is connected to a DTMF encoder 12 whose own output controls a switch 13. The switch 13 is located in the output path of the speech decoder 10.

In operation, signals transmitted by the encoding system of Fig 1 are received by the aerial 8 and radio receiver 9. The receiver 9 recovers speech signals from a speech channel and dialled digits from the signalling channel according to known principles.

The speech decoder 10 decodes any speech signal present from a digital to an analogue form and the DTMF encoder 12 regenerates the DTMF tones. Both decoder 10 and encoder 12 are commercially available devices.

The output of the encoder 15 controls the switch 13 located on the output line of the speech decoder 10. In this way the dialled digits are re-inserted into the speech path as DTMF tones. Using this method gives the advantage of allowing DTMF tones to be used for in-message signalling eg to control telephone answering machines, for touch-tone pad access to banking services, etc. However, it is important to compensate for delays in the system (particularly in the speech encoding and decoding processes and the radio air interface framing) to ensure that any residual DTMF tones which may be sent via the speech path are switched out either at the source end (by switch 13 or at the far end (by switch 5). This is achieved by the provision of the time delay module 11 which is present in the connection between the radio receiver 9 and the DTMF encoder 12. The module 11 acts by prolonging the time for which the DTMF encoder 12 operates by a time T, such that T is greater than the system delays.

The output line of the speech decoder 10 is routed to a telephone exchange which routes the call to its intended destination.

Claims (4)

1. Encoding apparatus having an input for connection to a telephone hand-set and an output for connection to a radio transmitter, said apparatus comprising: speech coding means for digitally encoding an analogue speech signal; means for detecting and digitally encoding dialling signals; and switching means, controlled by detecting and encoding means for inhibiting transmission of speech signals while said dialling signals are present at the input.
2. Decoding apparatus having an input for connection to a digital radio receiver and an output for connection to a telephone network, said apparatus comprising; speech decoding means for converting a digitally encoded speech signal into an analogue speech signal; encoding means for converting a digitally-encoded dialling signal into a DTMF signal; and switching means controlled by the encoding means for inhibiting transmission of analogue speech signals to the telephone network while a dialling signal is present at the input.
3. Encoding apparatus for use with a radiotelephone communications network substantially as hereinbefore described with reference to Fig 1 of the drawings.
4. Decoding apparatus for use with a radiotelephone communications network substantially as hereinbefore described with reference to Fig 2 of the drawings.
GB9127074A 1991-12-20 1991-12-20 Dialled digit handler Withdrawn GB2262683A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB9127074A GB2262683A (en) 1991-12-20 1991-12-20 Dialled digit handler

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB9127074A GB2262683A (en) 1991-12-20 1991-12-20 Dialled digit handler

Publications (2)

Publication Number Publication Date
GB9127074D0 GB9127074D0 (en) 1992-02-19
GB2262683A true GB2262683A (en) 1993-06-23

Family

ID=10706600

Family Applications (1)

Application Number Title Priority Date Filing Date
GB9127074A Withdrawn GB2262683A (en) 1991-12-20 1991-12-20 Dialled digit handler

Country Status (1)

Country Link
GB (1) GB2262683A (en)

Cited By (19)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2290005A (en) * 1994-05-28 1995-12-06 Motorola Ltd Communications system
EP0781062A2 (en) * 1995-12-21 1997-06-25 Nokia Mobile Phones Ltd. Radiotelephone system
WO2001063950A1 (en) * 2000-02-25 2001-08-30 Critical Telecom Corporation Wireless telephony interface and method
GB2422748A (en) * 2005-01-27 2006-08-02 Nicholas Paul Middleton Telecommunications apparatus
CN100334890C (en) * 1998-09-29 2007-08-29 西门子公司 Program-controlled communication system for switching analog and digital communication terminal equipment connected thereto
US7650425B2 (en) 1999-03-18 2010-01-19 Sipco, Llc System and method for controlling communication between a host computer and communication devices associated with remote devices in an automated monitoring system
US7697492B2 (en) 1998-06-22 2010-04-13 Sipco, Llc Systems and methods for monitoring and controlling remote devices
US7756086B2 (en) 2004-03-03 2010-07-13 Sipco, Llc Method for communicating in dual-modes
US8000314B2 (en) 1996-12-06 2011-08-16 Ipco, Llc Wireless network system and method for providing same
US8013732B2 (en) 1998-06-22 2011-09-06 Sipco, Llc Systems and methods for monitoring and controlling remote devices
US8031650B2 (en) 2004-03-03 2011-10-04 Sipco, Llc System and method for monitoring remote devices with a dual-mode wireless communication protocol
US8064412B2 (en) 1998-06-22 2011-11-22 Sipco, Llc Systems and methods for monitoring conditions
US8171136B2 (en) 2001-10-30 2012-05-01 Sipco, Llc System and method for transmitting pollution information over an integrated wireless network
US8335304B2 (en) 1997-02-14 2012-12-18 Sipco, Llc Multi-function general purpose transceivers and devices
US8410931B2 (en) 1998-06-22 2013-04-02 Sipco, Llc Mobile inventory unit monitoring systems and methods
US8489063B2 (en) 2001-10-24 2013-07-16 Sipco, Llc Systems and methods for providing emergency messages to a mobile device
US8666357B2 (en) 2001-10-24 2014-03-04 Sipco, Llc System and method for transmitting an emergency message over an integrated wireless network
US8787246B2 (en) 2009-02-03 2014-07-22 Ipco, Llc Systems and methods for facilitating wireless network communication, satellite-based wireless network systems, and aircraft-based wireless network systems, and related methods
US9439126B2 (en) 2005-01-25 2016-09-06 Sipco, Llc Wireless network protocol system and methods

Cited By (42)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2290005B (en) * 1994-05-28 1998-09-09 Motorola Ltd Communications system
GB2290005A (en) * 1994-05-28 1995-12-06 Motorola Ltd Communications system
EP0781062A2 (en) * 1995-12-21 1997-06-25 Nokia Mobile Phones Ltd. Radiotelephone system
EP0781062A3 (en) * 1995-12-21 1999-04-14 Nokia Mobile Phones Ltd. Radiotelephone system
US8982856B2 (en) 1996-12-06 2015-03-17 Ipco, Llc Systems and methods for facilitating wireless network communication, satellite-based wireless network systems, and aircraft-based wireless network systems, and related methods
US8000314B2 (en) 1996-12-06 2011-08-16 Ipco, Llc Wireless network system and method for providing same
US8233471B2 (en) 1996-12-06 2012-07-31 Ipco, Llc Wireless network system and method for providing same
US8335304B2 (en) 1997-02-14 2012-12-18 Sipco, Llc Multi-function general purpose transceivers and devices
US9430936B2 (en) 1998-06-22 2016-08-30 Sipco Llc Systems and methods for monitoring and controlling remote devices
US7697492B2 (en) 1998-06-22 2010-04-13 Sipco, Llc Systems and methods for monitoring and controlling remote devices
US9571582B2 (en) 1998-06-22 2017-02-14 Sipco, Llc Systems and methods for monitoring and controlling remote devices
US8964708B2 (en) 1998-06-22 2015-02-24 Sipco Llc Systems and methods for monitoring and controlling remote devices
US9691263B2 (en) 1998-06-22 2017-06-27 Sipco, Llc Systems and methods for monitoring conditions
US8064412B2 (en) 1998-06-22 2011-11-22 Sipco, Llc Systems and methods for monitoring conditions
US8410931B2 (en) 1998-06-22 2013-04-02 Sipco, Llc Mobile inventory unit monitoring systems and methods
US8212667B2 (en) 1998-06-22 2012-07-03 Sipco, Llc Automotive diagnostic data monitoring systems and methods
US8223010B2 (en) 1998-06-22 2012-07-17 Sipco Llc Systems and methods for monitoring vehicle parking
US8013732B2 (en) 1998-06-22 2011-09-06 Sipco, Llc Systems and methods for monitoring and controlling remote devices
US9129497B2 (en) 1998-06-22 2015-09-08 Statsignal Systems, Inc. Systems and methods for monitoring conditions
CN100334890C (en) * 1998-09-29 2007-08-29 西门子公司 Program-controlled communication system for switching analog and digital communication terminal equipment connected thereto
US8924588B2 (en) 1999-03-18 2014-12-30 Sipco, Llc Systems and methods for controlling communication between a host computer and communication devices
US8924587B2 (en) 1999-03-18 2014-12-30 Sipco, Llc Systems and methods for controlling communication between a host computer and communication devices
US8930571B2 (en) 1999-03-18 2015-01-06 Sipco, LLP Systems and methods for controlling communication between a host computer and communication devices
US7650425B2 (en) 1999-03-18 2010-01-19 Sipco, Llc System and method for controlling communication between a host computer and communication devices associated with remote devices in an automated monitoring system
WO2001063950A1 (en) * 2000-02-25 2001-08-30 Critical Telecom Corporation Wireless telephony interface and method
US8666357B2 (en) 2001-10-24 2014-03-04 Sipco, Llc System and method for transmitting an emergency message over an integrated wireless network
US9615226B2 (en) 2001-10-24 2017-04-04 Sipco, Llc System and method for transmitting an emergency message over an integrated wireless network
US8489063B2 (en) 2001-10-24 2013-07-16 Sipco, Llc Systems and methods for providing emergency messages to a mobile device
US10149129B2 (en) 2001-10-24 2018-12-04 Sipco, Llc Systems and methods for providing emergency messages to a mobile device
US9282029B2 (en) 2001-10-24 2016-03-08 Sipco, Llc. System and method for transmitting an emergency message over an integrated wireless network
US9515691B2 (en) 2001-10-30 2016-12-06 Sipco, Llc. System and method for transmitting pollution information over an integrated wireless network
US8171136B2 (en) 2001-10-30 2012-05-01 Sipco, Llc System and method for transmitting pollution information over an integrated wireless network
US9111240B2 (en) 2001-10-30 2015-08-18 Sipco, Llc. System and method for transmitting pollution information over an integrated wireless network
US8031650B2 (en) 2004-03-03 2011-10-04 Sipco, Llc System and method for monitoring remote devices with a dual-mode wireless communication protocol
US7756086B2 (en) 2004-03-03 2010-07-13 Sipco, Llc Method for communicating in dual-modes
US8446884B2 (en) 2004-03-03 2013-05-21 Sipco, Llc Dual-mode communication devices, methods and systems
US8379564B2 (en) 2004-03-03 2013-02-19 Sipco, Llc System and method for monitoring remote devices with a dual-mode wireless communication protocol
US10356687B2 (en) 2005-01-25 2019-07-16 Sipco, Llc Wireless network protocol systems and methods
US9860820B2 (en) 2005-01-25 2018-01-02 Sipco, Llc Wireless network protocol systems and methods
US9439126B2 (en) 2005-01-25 2016-09-06 Sipco, Llc Wireless network protocol system and methods
GB2422748A (en) * 2005-01-27 2006-08-02 Nicholas Paul Middleton Telecommunications apparatus
US8787246B2 (en) 2009-02-03 2014-07-22 Ipco, Llc Systems and methods for facilitating wireless network communication, satellite-based wireless network systems, and aircraft-based wireless network systems, and related methods

Also Published As

Publication number Publication date
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WAP Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1)