06330247 is referenced by 69 patents and cites 13 patents.

A method and apparatus for communicating both voice and control data between a communication device (such as a cellular phone) and an external accessory (such as a hands-free kit) over a data bus. The method includes formatting a sequence of bits into a repeating sequence of first time slots and second time slots, transmitting the voice data in the first time slot, and transmitting the control data in the second time slot. Notably, a first bit of each of the second time slots comprises a clock bit that alternates between a high value and a low value (e.g. a ‘1’ or a ‘0’) as between consecutive second time slots.

Title
Communication protocol between a communication device and an external accessory
Application Number
9/248514
Publication Number
6330247 (B1)
Application Date
February 8, 1999
Publication Date
December 11, 2001
Inventor
James Hutchison
San Diego
CA, US
Steven C Den Beste
San Diego
CA, US
Hanchi David Huang
San Diego
CA, US
Karthick Chinnaswami
San Diego
CA, US
George Pan
San Diego
CA, US
Robert Opalsky
San Diego
CA, US
Way Shing Lee
San Diego
CA, US
Chienchung Chang
San Diego
CA, US
Agent
Thomas R Rouse
US
Kent D Baker
US
Philip R Wadsworth
US
Assignee
Qualcomm Incorporated
CA, US
IPC
H04B 7/212
View Original Source