Device for adapting narrowband voice traffic of a local access network to ...

[54] DEVICE FOR ADAPTING NARROWBAND
VOICE TRAFFIC OF A LOCAL ACCESS
NETWORK TO ALLOW TRANSMISSION
OVER A BROADBAND ASYNCHRONOUS
TRANSFER MODE NETWORK

[75] Inventor: Frederick H. Skoog, Colleyville, Tex.

[73] Assignee: DSC Communications Corporation, Piano, Tex.

[21] Appl. No.: 408,698

[22] Filed: Mar. 21,1995

[51] Int. CI.6 H04L 12/66

[52] U.S. CI 370/397; 370/404; 370/466;

370/468; 370/477

[58] Field of Search 370/60.1,60,94.1,

370/94.2, 58.1, 58.2, 58.3, 110.1, 118, 32.1, 16.1, 95.1, 79, 84, 85.13; 379/3, 406, 410

[56] References Cited

U.S. PATENT DOCUMENTS

5,287,348 2/1994 Schmidt 370/60.1

5,301,189 4/1994 Schmidt 370/94.1

5,305,308 4/1994 English et al 370/32.1

5,327,421 7/1994 Hiller et al 370/60.1

5,375,118 12/1994 Rao et al 370/94.1

5,436,899 7/1995 Fujino et al 370/60

5,457,684 10/1995 Bharuchaetal 370/60.1

5,483,527 1/1996 Doshi et al 370/94.2

Primary Examiner—Wellington Chin

Assistant Examiner—Huy D. Vu

Attorney, Agent, or Firm—Baker & Botts, L.L.P.

[57] ABSTRACT

A voice adaptation device (18) provides an interface between a narrowband local access network and a broadband asynchronous transfer mode (ATM) backbone network (16). The voice adaptation device (18) includes a Tl/El network adaptor (50) that converts Tl/El signals carrying narrowband voice traffic into an ATM cell format. The Tl/El network adaptor (50) also performs echo cancelling, voice enhancement, digital voice protocol conversion, and compression/decompression on the narrowband voice traffic. The voice adaptation device (18) also includes a synchronous optical network formatter (52) that places ATM cells generated by the Tl/El network adaptor (50) into synchronous optical network signals. The synchronous optical network signals are transmitted across the broadband ATM backbone network (16).

11 Claims, 4 Drawing Sheets