GB2320645A - An apparatus for connecting a modem to a plurality of telephone lines - Google Patents
An apparatus for connecting a modem to a plurality of telephone lines Download PDFInfo
- Publication number
- GB2320645A GB2320645A GB9726967A GB9726967A GB2320645A GB 2320645 A GB2320645 A GB 2320645A GB 9726967 A GB9726967 A GB 9726967A GB 9726967 A GB9726967 A GB 9726967A GB 2320645 A GB2320645 A GB 2320645A
- Authority
- GB
- United Kingdom
- Prior art keywords
- modem
- signal output
- switch
- analog signal
- codec
- 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.)
- Granted
Links
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04M—TELEPHONIC COMMUNICATION
- H04M11/00—Telephonic communication systems specially adapted for combination with other electrical systems
- H04M11/06—Simultaneous speech and data transmission, e.g. telegraphic transmission over the same conductors
Landscapes
- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Telephonic Communication Services (AREA)
- Communication Control (AREA)
Abstract
An apparatus is disclosed comprising a first codec 16 which converts an analog signal output from the modem 10 into a PCM signal to be supplied to a time switch 18 and vice versa. Each of a plurality of further codecs 10-24 converts an analog signal output from a corresponding telephone TEL1-TEL2 line into a PCM signal to be supplied to the time switch 18 and vice versa. The time switch 18 transfers the digital signal output from the first codec 16 to a selected one of the further codecs 20-24 and vice versa, thereby loading the data on a respective channel. Connecting a modem to a plurality of telephone lines in this way allows the modem to continue communications even in the event of a line failure.
Description
1 APPARATUS FOR CONNECTING MODEM TO PUBLIC TELEPHONE LINE
Background of the Invention
The present invention relates to an apparatus for connecting a modem to a public telephone line in a data communication system.
2320645 In general, modems are connected between data communication systems to allow the transfer of data between them. Such modems are widely used for communication systems such as computers, cordless telephones (for example CT-2 (Cordless Telephone 2nd generation)), etc.
- 15 Fig. 1 illustrates a conventional connection between a modem and a public telephone line. As illustrated, a modem 10 has an input/output terminal which may be connected to selected telephone lines, through an analog switch 14. It should be noted that the analog switch 14 is connected between the modem 10 and the public telephone line, since the analog signal output from the modem 10 cannot directly be output to the telephone lines.
Therefore, if the telephone line assigned to the modem suffers a failure, the conventional system may not be able to continue data communication services. In general, since data communication usually involves transmission of important information such as system management information and billing information, failure of data communication may deal the communication system a severe blow. Further, input/output signals of the modem may be undesirably attenuated by the resistance of the analog switch.
Summary of the Invention
It is therefore an objective of the present invention to provide an improved apparatus for connecting a modem to a public telephone line.
2 It is another objective of the present invention to provide an apparatus for connecting a modem to a public telephone line, in which failure of a data communication can be prevented.
Accordingly, the present invention provides an apparatus for connecting a modem to a plurality of telephone lines in a data communication system, the apparatus comprising:
a first codec for converting an analog signal output from the modem into a digital signal and vice versa; a plurality of further codecs, each for converting an analog signal output from a corresponding telephone line into a digital signal and vice versa; and a switch for transferring the digital signal output from the f irst cddec to a selected one of the further codecs and vice versa.
Preferably, the first codec is adapted to convert the analog signal output from the modem into a PCM signal to be supplied to the switch and to convert a PCM signal output from the switch into an analog signal to be supplied to the modem.
Preferably, each of the further codecs is adapted to convert the analog signal output from the corresponding telephone line into a PCM signal to be supplied to the switch and to convert a PCM signal output from the switch into an analog signal to be supplied to that telephone line.
The switch may be a time switch.
Brief Description of the Drawings The present invention will now be described by way of example with reference to the accompanying drawings in which:
Fig. 1 is a block diagram showing a conventional connection between a modem and a public telephone line; and Fig. 2 is a block diagram showing a connection between 3 a modem and a public telephone line according to the present invention.
Detailed Description of the Preferred Embodiment
Fig. 2 illustrates a connection between a modem and a public telephone line according to the present invention, which can be used in a CT-2 base station connected to a plurality of telephone lines. Referring to Fig. 2, in a reception mode, a modem 10 is connected to a selected telephone line TEL1-TEL3 through a first codec 16, a time switch 18 and second to fourth codecs 20-24. If a voice signal is received through a first telephone line TEL1, the voice signal will be converted into a digital PCM (Pulse Code Modulation) signal by the second codec 20. The digital PCM signal is loaded on a particular channel by the time switch 18. The digital PCM signal on the particular channel is converted into an analog signal RX by the first codec 16. The analog signal RX from the first codec 16 is applied to the modem 10.
On the other hand, in a transmission mode, an analog signal TX generated from the modem 10 is converted by the codec 16 into a digital PCM signal and applied to the time switch 18. The time switch 18 transfers the digital PCM signal to a selected one of the second to fourth codecs 20-24. Then, the selected codec converts the received digital PCM signal into an analog signal and transmits the converted analog signal through the corresponding telephone line.
The time switch 18 functions as an exchange for switching the voice signal to a desired one of the telephone lines TEL1-TEL3. The analog signal output from the modem 10 cannot directly be applied to the time switch 18. Thus, in accordance with the present invention, the first codec 16 is interposed between the modem 10 and the time switch 18, to convert the analog signal output from the modem 10 into a digital signal and apply the converted digital signal to the time switch 18. Further, the first codec 16 converts the digital signal output from time switch 18 into an 4 analog signal and applies the converted analog signal to the modem 10.
As can be clearly appreciated from the foregoing 5 descriptions, if applied to a CT-2 base station connected to a plurality of telephone lines, the apparatus of the invention may successfully achieve data communication even if a failure has occurred on a particular telephone line. Further, the apparatus does not need the analog switch on a signal path of the modem, thereby solving the problem of unwanted signal attenuation. Moreover, the gain of the signal transferred to the modem from the first codec can be freely controlled, so that performance of the communication system can be improved.
Claims (5)
1. An apparatus for connecting a modem to a plurality of telephone lines in a data communication system, the apparatus comprising: a first codec for converting an analog signal output from the modem into a digital signal and vice versa; a plurality of further codecs, each for converting an analog signal output from a corresponding telephone line into a digital signal and vice versa; and a switch for transferring the digital signal output f rom the f irst codec to a selected one of the further codecs and vice versa.
2. Apparatus according to claim 1 in which the f irst codec is adapted to convert the analog signal output from the modem into a PCM signal to be supplied to the switch and to convert a PCM signal output from the switch into an analog signal to be supplied to the modem.
3. Apparatus according to claim 1 or claim 2 in which each of the further codecs is adapted to convert the analog signal output from the corresponding telephone line into a PCM signal to be supplied to the switch and to convert a PCM signal output from the switch into an analog signal to be supplied to that telephone line.
4. Apparatus according to any preceding claim in which the switch is a time switch.
5. An apparatus for connecting a modem to a plurality of telephone lines in a data communication system, the apparatus being substantially as described herein with reference to and/or as illustrated in FIG. 2 of the 35 accompanying drawings.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| KR1019960070561A KR19980051651A (en) | 1996-12-23 | 1996-12-23 | Connection between modem and public telephone line |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB9726967D0 GB9726967D0 (en) | 1998-02-18 |
| GB2320645A true GB2320645A (en) | 1998-06-24 |
| GB2320645B GB2320645B (en) | 1999-03-17 |
Family
ID=19490390
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB9726967A Expired - Fee Related GB2320645B (en) | 1996-12-23 | 1997-12-19 | Apparatus for connecting modem to public telephone line |
Country Status (7)
| Country | Link |
|---|---|
| JP (1) | JPH10200648A (en) |
| KR (1) | KR19980051651A (en) |
| CN (1) | CN1190831A (en) |
| DE (1) | DE19754862A1 (en) |
| FR (1) | FR2757728A1 (en) |
| GB (1) | GB2320645B (en) |
| RU (1) | RU2127492C1 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1914977A2 (en) * | 2006-10-18 | 2008-04-23 | Samsung Electronics Co., Ltd. | Facsimile Apparatus to Support a Plurality of Lines and Operating Method Thereof |
| US8155284B2 (en) | 2006-10-18 | 2012-04-10 | Samsung Electronics Co., Ltd. | Facsimile apparatus to support a plurality of lines and operating method thereof |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE102008053475B4 (en) | 2008-10-28 | 2019-09-05 | Dr. Ing. H.C. F. Porsche Aktiengesellschaft | Adjustable vehicle seat |
| RU2445744C1 (en) * | 2010-07-07 | 2012-03-20 | Общество С Ограниченной Ответственностью "Владимирский Завод "Электроприбор-1" | Coupling unit of device for coupling double-wire line with vhf radio station |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2766380B2 (en) * | 1990-06-19 | 1998-06-18 | 株式会社東芝 | Modem pooling system |
| DE4315621A1 (en) * | 1993-05-11 | 1994-11-17 | Sel Alcatel Ag | Interface arrangement for connecting base stations to a private branch exchange |
-
1996
- 1996-12-23 KR KR1019960070561A patent/KR19980051651A/en not_active Application Discontinuation
-
1997
- 1997-12-10 DE DE19754862A patent/DE19754862A1/en not_active Withdrawn
- 1997-12-19 GB GB9726967A patent/GB2320645B/en not_active Expired - Fee Related
- 1997-12-22 RU RU97122262A patent/RU2127492C1/en not_active IP Right Cessation
- 1997-12-22 JP JP9352501A patent/JPH10200648A/en active Pending
- 1997-12-22 FR FR9716241A patent/FR2757728A1/en active Pending
- 1997-12-23 CN CN97123450A patent/CN1190831A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1914977A2 (en) * | 2006-10-18 | 2008-04-23 | Samsung Electronics Co., Ltd. | Facsimile Apparatus to Support a Plurality of Lines and Operating Method Thereof |
| EP1914977A3 (en) * | 2006-10-18 | 2008-05-28 | Samsung Electronics Co., Ltd. | Facsimile Apparatus to Support a Plurality of Lines and Operating Method Thereof |
| US8155284B2 (en) | 2006-10-18 | 2012-04-10 | Samsung Electronics Co., Ltd. | Facsimile apparatus to support a plurality of lines and operating method thereof |
Also Published As
| Publication number | Publication date |
|---|---|
| GB9726967D0 (en) | 1998-02-18 |
| DE19754862A1 (en) | 1998-06-25 |
| JPH10200648A (en) | 1998-07-31 |
| KR19980051651A (en) | 1998-09-25 |
| GB2320645B (en) | 1999-03-17 |
| RU2127492C1 (en) | 1999-03-10 |
| FR2757728A1 (en) | 1998-06-26 |
| CN1190831A (en) | 1998-08-19 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 20081219 |