GB2295520A - Communications device having priority control - Google Patents

Communications device having priority control Download PDF

Info

Publication number
GB2295520A
GB2295520A GB9420822A GB9420822A GB2295520A GB 2295520 A GB2295520 A GB 2295520A GB 9420822 A GB9420822 A GB 9420822A GB 9420822 A GB9420822 A GB 9420822A GB 2295520 A GB2295520 A GB 2295520A
Authority
GB
United Kingdom
Prior art keywords
terminal equipment
item
communications device
communications
bus
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Withdrawn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
GB9420822A
Other versions
GB9420822D0 (en
Inventor
Andrew Thurling
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.)
KNX Ltd
Original Assignee
KNX 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 KNX Ltd filed Critical KNX Ltd
Priority to GB9420822A priority Critical patent/GB2295520A/en
Publication of GB9420822D0 publication Critical patent/GB9420822D0/en
Publication of GB2295520A publication Critical patent/GB2295520A/en
Withdrawn legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04Q—SELECTING
    • H04Q11/00—Selecting arrangements for multiplex systems
    • H04Q11/04—Selecting arrangements for multiplex systems for time-division multiplexing
    • H04Q11/0428—Integrated services digital network, i.e. systems for transmission of different types of digitised signals, e.g. speech, data, telecentral, television signals
    • H04Q11/0435—Details
    • H04Q11/0471—Terminal access circuits
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04Q—SELECTING
    • H04Q2213/00—Indexing scheme relating to selecting arrangements in general and for multiplex systems
    • H04Q2213/13106—Microprocessor, CPU
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04Q—SELECTING
    • H04Q2213/00—Indexing scheme relating to selecting arrangements in general and for multiplex systems
    • H04Q2213/13163—Fault alarm
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04Q—SELECTING
    • H04Q2213/00—Indexing scheme relating to selecting arrangements in general and for multiplex systems
    • H04Q2213/13173—Busy signals
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04Q—SELECTING
    • H04Q2213/00—Indexing scheme relating to selecting arrangements in general and for multiplex systems
    • H04Q2213/13209—ISDN
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04Q—SELECTING
    • H04Q2213/00—Indexing scheme relating to selecting arrangements in general and for multiplex systems
    • H04Q2213/1325—Priority service
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04Q—SELECTING
    • H04Q2213/00—Indexing scheme relating to selecting arrangements in general and for multiplex systems
    • H04Q2213/13271—Forced release
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04Q—SELECTING
    • H04Q2213/00—Indexing scheme relating to selecting arrangements in general and for multiplex systems
    • H04Q2213/13299—Bus
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04Q—SELECTING
    • H04Q2213/00—Indexing scheme relating to selecting arrangements in general and for multiplex systems
    • H04Q2213/25—Preferential service
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04Q—SELECTING
    • H04Q2213/00—Indexing scheme relating to selecting arrangements in general and for multiplex systems
    • H04Q2213/271—Forced release
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04Q—SELECTING
    • H04Q2213/00—Indexing scheme relating to selecting arrangements in general and for multiplex systems
    • H04Q2213/392—Channel allocation - special rules

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Data Exchanges In Wide-Area Networks (AREA)

Abstract

An item of terminal equipment 10 is connected to an ISDN exchange by an S-bus 2. A controller 14 controls input and output connections to the terminal equipment 10, in response to signals received from the ISDN exchange over the S-bus. The controller also monitors signals transmitted on the S-bus, but intended for other items of terminal equipment. In the case that a signal is transmitted to another item of terminal equipment, to indicate no channels being free, the controller may clear down at least one channel to which the terminal equipment 10 is presently connected, to allow the other item of terminal equipment to be connected. This is applicable where the other item of terminal equipment has a higher priority than the terminal equipment 10, and especially where the other item of terminal equipment has an alarm function. <IMAGE>

Description

COMMUNICATIONS DEVICES This invention relates to communications devices, and is concerned particularly, although not exclusively, with communications devices for use in ISDN systems.
In the UK, a typical ISDN system provides a basic rate service which operates on a bus interface, referred to as an S-BUS, which allows up to 8 separate items of terminal equipment to share a single basic rate line. The line typically provides two basic rate B-Channels, which may at any time be in use. If an item of terminal equipment requires use of a channel, it sends a signal to the ISDN exchange, requesting use of a channel. If both B-Channels are already in use, then the ISDN exchange will return a signal to the item of terminal equipment, refusing the request for the new call, and giving the reason that no channel is available.
In certain situations, it may be desirable to allocate a B-Channel to an item of terminal equipment as a high priority - for example, where that item of equipment generates an alarm call. Present communications devices simply allow an item of terminal equipment to be connected to or disconnected from a ISDN line, in dependence upon specific signals directed to the item of terminal equipment from the ISDN exchange.
Preferred embodiments of the present invention aim to provide communications devices incorporating an item of terminal equipment which may be disconnected from an ISDN line, in the event that another item of terminal equipment is trying to connect to the same line.
More generally, according to one aspect of the present invention, there is provided a communications device comprising a first item of terminal equipment for connection to a communications exchange by way of a multichannel bus to which at least one second item of terminal equipment is connected, the device comprising: input means for receiving signals placed on the bus by the communications exchange; discriminating means for discriminating between first and second signals of said signals received by said input means, said first signals carrying an identifier corresponding to said first item of terminal equipment, and each said second signal carrying an identifier corresponding to a respective said second item of terminal equipment; and control means for controlling operation of said communications device in a first mode, in response to said first signals, and for controlling operation of said communications device in a second mode, in response to said second signals.
Preferably, in said first mode, said control means controls operation of said communications device to connect or disconnect said first item of terminal equipment to or from said communications exchange.
Preferably, in said second mode, said control means controls operation of said communications device to disconnect said first item of terminal equipment from said communications exchange, on at least one channel.
At least one of said second signals may carry an identifer for a respective said second item of terminal equipment that is operative to signal an alarm condition.
In said second mode, said control means may control operation of said communications device to record or otherwise store data derived from the respective said second signal.
Preferably, said communications exchange is an ISDN exchange.
Preferably, said bus is an S-BUS.
Preferably, said S-BUS has a plurality of B-Channels by which said items of terminal equipment are connectable to said communications exchange.
The invention extends to a communications system comprising a communications device according to any of the preceding aspects of the invention which, together with said second item(s) of terminal equipment, is connected to said communications exchange by way of said multi-channel bus.
For a better understanding of the invention, and to show how embodiments of the same may be carried into effect, reference will now be made, by way of example, to the accompanying diagrammatic drawings, in which: Figure 1 illustrates schematically an ISDN exchange and a plurality of items of terminal equipment connected thereto; and Figure 2 is a block schematic diagram of one example of a communications device according to one aspect of the present invention.
In Figure 1, a plurality of items of terminal equipment TE1 to TEn are connected to an ISDN exchange 1 by way of an S-BUS 2, which provides two basic rate B-Channels.
In normal use, any item of terminal equipment Tx which requires use of a B-Channel sends a request to the ISDN exchange, by way of an appropriate signal which includes a unique Terminal Endpoint Id TEI. If a B-Channel is free, then the ISDN exchange 1 places a return signal on the S-BUS, including the respective TEI, and indicating that either a channel is available and connection can be made, or that there is no free channel available, so that no connection can be made.
Typically, each item of terminal equipment TEl to TEn monitors each signal placed on the S-BUS. If it detects a signal with its own unique TEI, it responds to that signal. Otherwise, it ignores the signal.
The communications device 20 that is shown in Figure 2 comprises an item of terminal equipment 10 that is connected to the S-BUS 2 via an input/output (I/O) device 11. The item of terminal equipment 10 may be of any desired type or configuration. In the present example, it provides connections to a telephone 12 or a computer 13, in order to transmit voice and data signals respectively.
The I/O device 11 and terminal equipment 10 are controlled by a controller 14, which also controls a data store 15, a print device 16 and a display device 17, all of which are optional devices. A discriminator 18 discriminates signals passed from the I/O device 11 to the controller 14.
An example of operation of the communications device 20 is as follows.
In normal use, the terminal equipment 10 is controlled by the controller 14 to send a call request signal to the ISDN exchange 1, through the I/O device 11 and over the S-BUS 2. The ISDN exchange places a reply signal on the S-BUS 2, including a TEI unique to the terminal equipment 10. The TEI is detected by the discriminator 18, which provides an appropriate signal to the controller 14, to indicate the contents of the message returned from the ISDN exchange, together with an indication that the signal is addressed to the terminal equipment 10, by way of the unique TEI. The terminal equipment 10 is then either connected to or disconnected from one of the B-Channels on the S-BUS 2, in dependence upon the reply signal received from the ISDN exchange. If there is a B-Channel free, then a connection will be made. If there is no channel free, then a connection will not be made. If the terminal equipment 10 has completed a call, then it will be cleared down from its respective B-Channel, upon receipt of the reply signal from the ISDN exchange.
Typically, messages over the S-BUS will conform to the CCITT Q931 standard, which will be understood by all items of terminal equipment on the exchange network.
In addition to monitoring signals on the S-BUS 2 that are addressed to the terminal equipment 10, the communications device 20 also monitors continually signals placed on the S-BUS 2 by the ISDN exchange, that are intended for other items of terminal equipment. Thus, the discriminator 18 is operative to pass to the controller 14 a signal that has been placed on the S-BUS 2, together with an indication that the signal was intended for an item of terminal equipment other than the terminal equipment 10.
In the event that such a signal is received by the controller 14, indicating that another item of terminal equipment has been cleared due to there being no channels available, the controller 14 is operative to control the communications device 20 in a second mode. In the second mode, the terminal equipment 10 is cleared from at least one of the B-Channels on the S-BUS 2, to make that channel available for another item of terminal equipment.
Provided that the other item of terminal equipment that was requesting a channel continues to retry after a short delay (eg of the order of 2 seconds), it will be able to be connected to the B-Channel from which the terminal equipment 10 has just been cleared.
As a more detailed example of this mode of operation, the communications device 20 may continually monitor RELEASE COMPLETE messages coming from the ISDN exchange 1. If the RELEASE COMPLETE message (hex SA) has a CAUSE information element coded 02 A2, then this indicates that the RELEASE COMPLETE message has been sent due to their being no channels available. The code 02 indicates that the message has originated from the local ISDN exchange, and the code A2 indicates that no free channel is available.
As indicated above, the TEI attaching to this message is discriminated by the discriminator 18, to determine whether the message is for the terminal equipment 10 or for another item of terminal equipment.
If the latter, the controller 14 checks how many B-Channels are presently allocated to the terminal equipment 10. If no channels are allocated, or if only one channel is allocated, then the controller 14 needs to take no further action. However, if two B-Channels are allocated, then the controller 14 is operative to cause one channel at least to be cleared down. For example, the controller may have a logical function such that a data channel is cleared in preference to a voice channel. If both channels are allocated to an aggregated data call (that is, both channels are used simultaneously for the transfer of one batch of data), then both the channels will be cleared.
The discriminator 18 may discriminate signals intended for other items of terminal equipment in one of two ways.
Firstly, it may simply determine whether the TEI is for an item of terminal equipment other than the terminal equipment 10. Secondly, if each item of terminal equipment TE1 to TEn has its own unique TEl, the discriminator 18 can identify in each case the item of terminal equipment for which the signal from the ISDN exchange 1 is intended.
In this latter case, the controller 14 can decide whether or not to release one or more of any occupied B-Channels from the terminal < quipment 10, independent upon whether the detected signal is intended for an item of terminal equipment that has a higher or lower priority than the terminal equipment 10. For example, if the other item of terminal equipment is for an alarm function, then it may automatically take priority over the terminal equipment 10.
Other embodiments of the invention may be adapted for alternative uses. For example, when operating in a second mode, upon detecting a signal from the ISDN exchange that is intended for another item of terminal equipment, the controller may be operative to provide an alarm to which a user may respond. Data may be stored as to the usage (or attempted usage) of terminal equipment other than the terminal equipment 10. If each item of terminal equipment has its own TEI, then usage of the individual items of terminal equipment can be monitored. Such data may be stored in the data store 15, printed on the printer 16 and/or displayed on the display 17.
An example of an alternative use of a modified embodiment of the invention is to log the number of times that a channel request is refused by the ISDN exchange, due to there being no channels available. This can give an indication of any need for additional lines.
The reader's attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.
All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.
Each feature disclosed in this specification (including any accompanying claims, abstract and drawings), may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.
The invention is not restricted to the details of the foregoing embodiment(s). The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

Claims (10)

1. A communications device comprising a first item of terminal equipment for connection to a communications exchange by way of a multi-channel bus to which at least one second item of terminal equipment is connected, the device comprising: input means for receiving signals placed on the bus by the communications exchange; discriminating means for discriminating between first and second signals of said signals received by said input means, said first signals carrying an identifier corresponding to said first item of terminal equipment, and each said second signal carrying an identifier corresponding to a respective said second item of terminal equipment; and control means for controlling operation of said communications device in a first mode, in response to said first signals, and for controlling operation of said communications device in a second mode, in response to said second signals.
2. A communications device according to claim 1, wherein, in said first mode, said control means controls operation of said communications device to connect or disconnect said first item of terminal equipment to or from said communications exchange.
3. A communications device according to claim 1 or 2, wherein, in said second mode, said control means controls operation of said communications device to disconnect said first item of terminal equipment from said communications exchange, on at least one channel.
4. A communications device according to claim 1, 2 or 3, wherein at least one of said second signals carries an identifer for a respective said second item of terminal equipment that is operative to signal an alarm condition.
5. A communications device according to any of the preceding claims, wherein, in said second mode, said control means controls operation of said communications device to record or otherwise store data derived from the respective said second signal.
6. A communications device according to any of the preceding claims, wherein said communications exchange is an ISDN exchange.
7. A communications device according to claim 6, wherein said bus is an S-BUS.
8. A communications device according to claim 7, wherein said S-BUS has a plurality of B-Channels by which said items of terminal equipment are correctable to said communications exchange.
9. A communications device substantially as hereinbefore described with reference to Figures 1 and 2 of the accompanying drawings.
10. A communications system comprising a communications device according to any of the preceding claims which, together with said second item(s) of terminal equipment, is connected to said communications exchange by way of said multi-channel bus.
GB9420822A 1994-10-15 1994-10-15 Communications device having priority control Withdrawn GB2295520A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB9420822A GB2295520A (en) 1994-10-15 1994-10-15 Communications device having priority control

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB9420822A GB2295520A (en) 1994-10-15 1994-10-15 Communications device having priority control

Publications (2)

Publication Number Publication Date
GB9420822D0 GB9420822D0 (en) 1994-11-30
GB2295520A true GB2295520A (en) 1996-05-29

Family

ID=10762905

Family Applications (1)

Application Number Title Priority Date Filing Date
GB9420822A Withdrawn GB2295520A (en) 1994-10-15 1994-10-15 Communications device having priority control

Country Status (1)

Country Link
GB (1) GB2295520A (en)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2326794A (en) * 1997-05-12 1998-12-30 Rolm Systems ISDN bandwidth allocation
EP0891115A1 (en) * 1997-07-07 1999-01-13 Siemens Business Communication Systems, Inc. Methods and apparatus for facilitating communication between multiple platforms via a single, multi-channel communication conduit
WO2003101145A1 (en) * 2002-05-08 2003-12-04 Eccleshill Limited Isdn interface apparatus
FR2870417A1 (en) * 2004-05-17 2005-11-18 France Telecom Telecommunication terminal for digital integrated services network, has processor with software to detect identifier of each telephonic terminal, where terminal transmits message over network by utilizing identifier
FR2870419A1 (en) * 2004-05-17 2005-11-18 France Telecom Communication establishing process for integrated services digital network, involves causing break of communication established from online terminal upon detection of conflict of terminal identifier

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0320890A2 (en) * 1987-12-14 1989-06-21 Nec Corporation Simple adapter for multiplexing ISDN terminals
WO1992021187A1 (en) * 1991-05-23 1992-11-26 Bell Atlantic Network Services, Inc. Dynamic channel allocation method and system for integrated services digital network
US5365517A (en) * 1992-09-04 1994-11-15 Ricoh Company, Ltd. ISDN Terminal equipment

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0320890A2 (en) * 1987-12-14 1989-06-21 Nec Corporation Simple adapter for multiplexing ISDN terminals
WO1992021187A1 (en) * 1991-05-23 1992-11-26 Bell Atlantic Network Services, Inc. Dynamic channel allocation method and system for integrated services digital network
US5365517A (en) * 1992-09-04 1994-11-15 Ricoh Company, Ltd. ISDN Terminal equipment

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2326794A (en) * 1997-05-12 1998-12-30 Rolm Systems ISDN bandwidth allocation
GB2326794B (en) * 1997-05-12 2002-07-31 Siemens Business Comm Systems Method and apparatus for dynamically allocating bandwith to independent data and audio devices
EP0891115A1 (en) * 1997-07-07 1999-01-13 Siemens Business Communication Systems, Inc. Methods and apparatus for facilitating communication between multiple platforms via a single, multi-channel communication conduit
WO2003101145A1 (en) * 2002-05-08 2003-12-04 Eccleshill Limited Isdn interface apparatus
FR2870417A1 (en) * 2004-05-17 2005-11-18 France Telecom Telecommunication terminal for digital integrated services network, has processor with software to detect identifier of each telephonic terminal, where terminal transmits message over network by utilizing identifier
FR2870419A1 (en) * 2004-05-17 2005-11-18 France Telecom Communication establishing process for integrated services digital network, involves causing break of communication established from online terminal upon detection of conflict of terminal identifier

Also Published As

Publication number Publication date
GB9420822D0 (en) 1994-11-30

Similar Documents

Publication Publication Date Title
US5384766A (en) LAN management system in electronic switching apparatus
EP0475749B1 (en) ISDN terminal having diagnostic function
GB2295520A (en) Communications device having priority control
EP0665700A1 (en) Method and system for radio-communication set-up and receiving device therefor
JP2632550B2 (en) ISDN subscriber wireless communication system
US6031824A (en) Maintenance and supervisory control method and system for multiplex communication equipment
JP2874503B2 (en) In-system broadcast method of user / user information
KR100268225B1 (en) Maintenance method for connection an(access network) and le(logical exchage) using v5.2
KR100342486B1 (en) Integrated digital loop carrier service method for integrated services digital network in multiplex apparatus
JP4353559B2 (en) Forced line connection device
JPS63202153A (en) Communication equipment
JP3310339B2 (en) ISDN terminal equipment
JPS61148599A (en) Security signal receiver
JPH0746340A (en) Monitoring image communications system
JP2804490B2 (en) Communication management device for ISDN terminal
JP2868077B2 (en) ISDN terminal adapter with optical interface
JP2000269965A (en) Atm multiplexer and method for informing of congestion
JPH0774848A (en) Isdn subscriber device
JPH0530075A (en) Bi-directional line management system
JPH04170145A (en) Remote supervisory system
JPH07221755A (en) Communication interface circuit
JP2000067354A (en) Remote monitoring device
JP2003008759A (en) Automatic sensing system
JPH05250199A (en) Duplex switching system
GB2285192A (en) Network surveillance

Legal Events

Date Code Title Description
WAP Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1)