John E Vandermeer

US Patent:

56469462, Jul 8, 1997

Filed:

Oct 30, 1995

Appl. No.:

8/550036

Inventors:

John E. VanderMeer - Austin TX
Duncan M. Fisher - Mission Viejo CA
Tan Nhat Dao - Austin TX

Assignee:

Motorola, Inc. - Schaumburg IL

International Classification:

H04J 302

US Classification:

370442

Abstract:

A data processing system (10) and associated method (150) of operation selectively compand data on a slot-by-slot basis. The data processing system (10) includes a processor (12), processor bus (14), memory (16), output serial interface (18), and input serial interface (70). The output serial interface (18) includes an output data buffer (20), compression module (22), output shift register (24), and output controller (26). In operation, the output serial interface (18) receives output data (28) and selectively compresses the data on a slot-by-slot basis. The shift register (24) then places the transmit data (32) on the serial link (25). An input serial interface (128) selectively expands data received on the serial link (25) on a slot-by-slot basis to produce input data (82). The associated method (150) includes method steps for companding data on a slot-by-slot basis. An ISDN interface and digital telephone (200) employ the teachings of the present invention.