ISDN terminal adapter for use with external modem and employing software-based serial communication framing for ISDN `D` channel signaling

• US 5,903,572 A
• Filed: 09/04/1997
• Issued: 05/11/1999
• Est. Priority Date: 04/22/1996
• Status: Expired due to Term

• Current Assignee: ADTRAN Incorporated (ADTRAN Holdings, Inc.)
• Original Assignee: ADTRAN Incorporated (ADTRAN Holdings, Inc.)
• Inventors: Wright, Jonathan A., Glass, James M. III, McElroy, Paul G.
• Primary Examiner(s): Patel, Ajit
• Application Number:
  US08/923,100
• Time in Patent Office: 614 Days
• Field of Search: 370/264, 370/524, 370/522, 370/265, 370/463, 379/93, 379/94, 379/88, 379/89, 379/97, 379/98, 375/222
• US Class Current: 370/524
• CPC Class Codes: H04Q 11/0471 Terminal access circuits
• CPC Class Codes: H04Q 2213/13034 A/D conversion, code compression/expansion
• CPC Class Codes: H04Q 2213/1305 Software aspects
• CPC Class Codes: H04Q 2213/1309 Apparatus individually associated with a subscriber line, line circuits
• CPC Class Codes: H04Q 2213/13096 Digital apparatus individually associated with a subscriber line, digital line circuits
• CPC Class Codes: H04Q 2213/13106 Microprocessor, CPU
• CPC Class Codes: H04Q 2213/13176 Common channel signaling, CCS7
• CPC Class Codes: H04Q 2213/13199 Modem, modulation
• CPC Class Codes: H04Q 2213/13202 Network termination [NT]
• CPC Class Codes: H04Q 2213/13209 ISDN
• CPC Class Codes: H04Q 2213/13292 Time division multiplexing, TDM
• CPC Class Codes: H04Q 2213/13299 Bus
• CPC Class Codes: H04Q 2213/1332 Logic circuits

Abstract

An ISDN terminal adapter is capable of providing both digital and analog communication connectivity between a customer'"'"'s data terminal equipment (DTE) and a digital communication link. The adapter includes a digital (ISDN) communication transceiver for transmitting and receiving digital communication signals on the ISDN link. A first digital communication connector is coupled with the DTE. A second digital communication connector is coupled with the customer'"'"'s modem. An analog communication connector is coupled with an analog port of the modem. An analog/digital communication interface is coupled between the analog communication connector and the digital communication transceiver. A serial communication exchange processor is coupled with the first and second digital communication connectors and the transceiver. For all-digital (ISDN) connectivity, the processor provides a first communication path, exclusive of the modem, between the first digital communication connector and the transceiver, so that digitally formatted communication may take place between the DTE and the ISDN link. For digital-analog connectivity, the processor provides a second communication path that makes use of the customer'"'"'s external modem, between the first digital communication connector and the transceiver, for communications between the DTE and the ISDN link.

Claims

1. An apparatus for interfacing digital terminal equipment with a communication link, said apparatus comprising:

a transceiver which is operative to send and receive digital communication signals via said digital communication link;

a first digital port to which a digital communication port of said digital terminal equipment is connectable;

a second digital port to which a digital communication port of a modem is connectable;

a first analog port to which an analog communication port of said modem is connectable;

a first analog/digital communication interface coupled between said first analog port and said first transceiver; and

a communication processor, coupled with said first and second digital ports and said transceiver, and being operative to control establishment of digitally formatted communications through said modem between said digital terminal equipment and said communication link, by selectively providing one of;

1--a first path, exclusive of said modem, between said first digital port and said first transceiver, and

2--a second path, inclusive of said modem, between said transceiver and said first analog/digital communication interface.

2. An apparatus according to claim 1, wherein said communication processor includes a first serial communication controller coupled to said first digital port, a second serial communication controller coupled to said second digital port, and a third serial communication controller coupled to said transceiver, said communication processor establishing said first path between said digital terminal equipment and said transceiver by selectively providing serial communication connectivity between said first serial communication controller and said third serial communication controller.

3. An apparatus according to claim 2, wherein said transceiver comprises an integrated services digital network (ISDN) transceiver, and said communication processor further includes fourth and fifth serial communication controllers respectively coupled to said ISDN transceiver, said fourth and fifth serial communication controllers being associated with bearer (B) channels of said ISDN transceiver.

4. An apparatus according to claim 1, wherein said communication processor includes a first communication controller coupled to said first digital port, and a second serial communication controller coupled to said digital port, said communication processor providing said second path through said first digital port, said first serial communication controller, said second serial communication controller, said second digital port, said modem, said first analog port, and said first analog/digital communication interface to said transceiver.

5. An apparatus according to claim 1, further including a multiplexer--demultiplexer having a first port coupled to said first digital port, a second port coupled to said second digital port, and a third port, and wherein said communication processor includes a first serial communication controller coupled to said third port of said multiplexer--demultiplexer, and a second serial communication controller coupled to said transceiver, and wherein said communication processor is operative to selectively provide said first path between said first digital port, through said communication multiplexer--demultiplexer, to said first serial communication controller, and between said first and said second serial communication controllers, so as to provide said first path through said multiplexer--demultiplexer between said digital terminal equipment and said transceiver.

6. An apparatus according to claim 5, wherein said transceiver comprises an integrated services digital network (ISDN) transceiver having a high speed data port, and wherein said communication processor further includes an interrupt port directly coupled to said high speed data port of said digital communication transceiver for interfacing a signalling (D) channel for said ISDN transceiver, and wherein said second serial communication controller is associated with a bearer (B) channel for said ISDN transceiver.

7. An apparatus according to claim 1, wherein said communication processor includes a first serial communication controller, and further including a multiplexer--demultiplexer having a first port coupled to said first digital port, a second port coupled to said second digital port, and a third port coupled to said first serial communication controller, and wherein said communication processor selectively provides a second path between said first digital port, through said multiplexer--demultiplexer, to said second digital port, and thereby between said digital terminal equipment and said transceiver.

8. An apparatus according to claim 1, wherein said modem is external to said digital terminal equipment.

9. An apparatus according to claim 8, wherein said second path includes a path between said second digital port and said first analog port.

10. An apparatus according to claim 1, wherein said modem is internal of said digital terminal equipment.

11. An apparatus according to claim 10, wherein said second path includes said digital terminal equipment, said modem, said first analog port and said first analog/digital communication interface.

12. An apparatus according to claim 1, further including a second analog port arranged to be coupled with an analog communication device, and a second analog/digital communication interface coupled between said second analog port and said transceiver.

13. An ISDN terminal adapter comprising an ISDN transceiver for transmitting and receiving ISDN communication signals, a first digital port coupled with a digital communication port of digital terminal equipment, a second digital port coupled with a digital port of a modem, a first analog port coupled with an analog port of said modem, a first analog/digital communication interface coupled between said first analog port and said ISDN transceiver, and a communication processor coupled with said first and second digital ports and said ISDN transceiver, and wherein said processor, in response to a request for digital connectivity with a communication circuit, is operative to provide a first path, exclusive of said modem, between said first digital port and said ISDN transceiver, so that ISDN communications may take place between said digital terminal equipment and said communication circuit, and, in response to a request for analog connectivity with said communication circuit, to provide a second path through said modem, said first analog port, said first analog/digital communication interface and said ISDN transceiver.

14. An ISDN terminal adapter according to claim 13, further including a second analog port arranged to be coupled with an analog communication device, and a second analog/digital communication interface coupled between said second analog port and said ISDN transceiver.

15. An ISDN terminal adapter according to claim 13, further including a multiplexer--demultiplexer having first and second ports respectively coupled to said first and second digital ports, and a third port, and wherein said communication processor includes a first serial communication controller coupled to said third port of said multiplexer--demultiplexer, and a second serial communication controller coupled to said ISDN transceiver, and wherein said communication processor is operative to selectively provide said first path between said first digital port, through said multiplexer--demultiplexer, to said first serial communication controller, and between said first and said second serial communication controllers, so as to provide said first path through said multiplexer--demultiplexer between said digital terminal equipment and said ISDN transceiver.

16. An ISDN terminal adapter according to claim 15, wherein said ISDN transceiver has a high speed data port, and wherein said communication processor further includes an interrupt port directly coupled to said high speed data port of said ISDN transceiver for interfacing a signalling (D) channel for said ISDN transceiver under software control, and wherein said second serial communication controller is associated with a bearer (B) channel for said ISDN transceiver.

17. An ISDN terminal adapter comprising:

an ISDN transceiver for transmitting and receiving ISDN communication signals, said ISDN transceiver having a high speed data port;

a digital port coupled with a digital communication port of digital terminal equipment; and

a serial communications processor coupled with said digital port and said ISDN transceiver, and being operative, in response to a request for digital connectivity with a communication circuit, to provide a path between said digital port and said ISDN transceiver, so that ISDN communications may take place between said digital terminal equipment and said communication circuit, said serial communications processor including an interrupt port coupled to said high speed data port of said ISDN transceiver for interfacing a signalling (D) channel for said ISDN transceiver under software control.

18. An ISDN terminal adapter according to claim 17, wherein said communications processor includes a serial communication controller associated with and coupled to said digital port, and a further serial communication controller coupled to said ISDN transceiver, and wherein said serial communications processor is operative to selectively provide said path between said digital port and said associated serial communication controller, and between said associated serial communication controller and said further serial communication controller, so as to provide said path between said digital terminal equipment and said ISDN transceiver.

19. An ISDN terminal adapter according to claim 18, wherein said further serial communication controller comprises first and second serial communication controllers which are operative to interface bearer (B) channel data with said ISDN transceiver.