05003576 is referenced by 84 patents and cites 46 patents.

An analog-to-digital voice storage cellular telephone for recording voice messages while the user is away from the cellular telephone unit. In a preferred embodiment, the analog-to-digital voice storage cellular telephone comprises call answering circuitry which is activated after a predetermined number of rings. Detection circuitry waits to detect a SAT signal during a preset period of time. Once the SAT signal is detected a prerecorded outgoing message is transmitted to the caller. The voice storage cellular telephone records incoming voice messages which are retrieved and replayed by users at their convenience. If the SAT signal is not detected, call terminating circuitry immediately terminates call. In accordance with one aspect, voice messages may be recorded at the central cellular station in real time, subsequently transmitted to the voice storage cellular telephone at a high speed and reproduced at normal speed to reduce air transmission time and cost.

Title
Analog/digital voice storage cellular telephone
Application Number
77496
Publication Number
5003576
Application Date
April 14, 1989
Publication Date
March 26, 1991
Inventor
Richard J Helferich
154 Donegal Ave., Newbury Park, 91320-3420
CA, US
Agent
Knobbe Martens Olson & Bear
Assignee
Martin A Schwartz
CA, US
Richard J Helferich
CA, US
IPC
H04M 11/00
H04M 1/65
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