Telephone system and method for transmitting digital information

• US 4,750,169 A
• Filed: 03/11/1986
• Issued: 06/07/1988
• Est. Priority Date: 03/12/1985
• Status: Expired due to Term

• Current Assignee: Pacific Bell (AT&T, Inc.)
• Original Assignee: Pacific Bell (AT&T, Inc.)
• Inventors: Daines, Bernard N., Carse, Gregg D.
• Primary Examiner(s): Olms, Douglas W.
• Assistant Examiner(s): Chin, Wellington
• Application Number:
  US06/838,579
• Time in Patent Office: 819 Days
• Field of Search: 370/109, 370/110.1, 370/29, 370/24
• US Class Current: 370/521
• CPC Class Codes: H04M 11/068 using time division multiplex techniques; integrated services digital networks H04Q11/0428
• CPC Class Codes: H04Q 11/0428 Integrated services digital network, i.e. systems for transmission of different types of digitised signals, e.g. speech, data, telecentral, television signals

Abstract

A telephone system is described wherein a plurality of subscriber locations are each connected to a central office by a single subscriber loop. A signalling method is used for transmitting information between each subscriber location and a cental office. Bursts of time compressed multiplexed full duplex digital signals are synchronously transmitted at an information bit rate of between about forty and eighty kilobits per second and at a burst cycle of between about 0.8 and 4.0 milliseconds. Each of the bursts is comprised of bits defining at least one voice channel, at least one data channel, and at least one signalling channel, with at least one synchronizing bit at the front and back of each burst.

Claims

1. In a telephone system wherein a plurality of subscriber locations are each connected to a central office by a single subscriber loop, a signaling method for transmitting full duplex information between each of the subscriber locations and a central office, said method comprising, transmitting bursts of time compressed multiplexed digital signals at an information bit rate of between about 40 and 80 kilobits per second on the subscriber loops, said transmitting step including transmitting the bursts from the central office to all of the subscriber locations substantially simultaneously with each other, and transmitting the bursts from all of the subscriber locations to the central office such that said bursts arrive at the central office substantially simultaneously with each other.

2. A method according to claim 1 wherein the bursts are transmitted at a burst cycle of between about 0.8 and 4.0 milliseconds.

3. A method according to claim 1 wherein each of said bursts comprises bits defining at least one voice channel, at least one data channel, and at least one signaling channel, and comprising at least one synchronizing bit at the front and back of each said burst.

4. A method according to claim 1 wherein each burst comprises bits defining two voice channels.

5. A method according to claim 1 wherein each burst comprises a plurality of data channels.

6. A method according to claim 1 wherein each burst comprises two voice channels, a medium speed data channel, and four low speed data channels.

7. A method according to claim 1 wherein the bits in each burst are allocated to a plurality of channels, with the number of bits in each channel being at least equal to the minimum required for simulating a hand-wired single channel connection between the subscriber location and the central office for the data assigned to each channel.

8. A method according to claim 1 wherein the amplitude of the bursts transmitted from the subscriber location to the central office is controlled such that the bursts arriving at the central office are of substantially equal aplitude.

9. In a data transfer system wherein a plurality of remote locations are each connected to a central location by a single wired loop respectively, a signaling method for full duplex transmission of information between each remote location and a central location, said method comprising, transmitting bursts of time compressed multiplexed digital signals at an information bit rate of between about 40 and 80 kilobits per second on the wired loops, said transmitting step including transmitting the bursts directed from the central location to all of the remote locations substantially simultaneously with each other, and transmitting the bursts from all of the remote locations to the central location such that said bursts arrive at the central location substantially simultaneously with each other.

10. A method according to claim 9 wherein the amplitude of the bursts transmitted from the subscriber location to the central office is controlled such that the bursts arriving at the central office are of substantially equal amplitude.