04837858 is referenced by 157 patents and cites 16 patents.

A trunked voice/data subscriber is provided that operates in either a voice mode, or one of three data modes. In a first data mode, the voice/data subscriber monitors the voice control channel to enable rapid participation in a voice call. In a second data mode, the subscriber monitors an assigned data channel until either commanded to change modes or until there has been no data activity for a predetermined time interval. Lastly, the subscriber may operate to remain in the last mode used so that, over time, the subscriber resides primarily in the mode predominately used. According to the invention, the voice/data subscriber must request a channel for each voice transmission. However, a data channel request need only be transmitted in no data channels are currently reallocated. If a data channel has been allocated, the subscriber may transmit at any time without first requesting access.

Title
Subscriber unit for a trunked voice/data communication system
Application Number
7/44392
Publication Number
4837858
Application Date
April 30, 1987
Publication Date
June 6, 1989
Inventor
Kenneth J Zdunek
Schaumburg
IL, US
Stuart W Thro
Cary
IL, US
Sewim F Ablay
Hoffman Estates
IL, US
Agent
Wayne J Egan
Thomas G Berry
Assignee
Motorola
IL, US
IPC
H04J 3/16
H04B 7/14
H04Q 7/00
H04M 11/00
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