Oki Telecom, Inc.

Oki Electric Ind., Ltd.

Stephen T Hardin

Clifton J Barber

Masayuki Higuchi

Tsuyosi Otake

A method and an apparatus for selecting a cellular carrier frequency for accessing cellular airtime services based upon a list of preferred system identification codes (SIDs). A cellular telephone is programmed to accept into memory a list of preferred SIDs corresponding to carriers through which service is preferred. While any SID remains in a preferred list, the standard A/B system selection function is replaced by a substitute system selection function which includes only three carrier selection modes including the Home Only mode, the SID Only mode, and a Roam Saver mode. With the Roam Saver carrier selection mode, the cellular telephone first prefers service through a home carrier and then through a carrier broadcasting a SID matching a SID on the preferred list, but never denies service to emergency or non-emergency destinations if any SID is detected. Status indicators are used to, among other purposes, differentiate between no service being available, service being available through a carrier broadcasting a home SID, a preferred SID, or a non-preferred available SID. Also, in addition to multiple number assignment modules (NAMs) being included to support subscriptions to services from multiple carriers, the user is provided the option of manually selecting which NAM is used or enabling the cellular telephone, through an auto-NAM function, to automatically select and use the NAM of any home carrier detected by the cellular telephone.

Preferred carrier selection method

Cellular carrier selection system incorporating a preferred list of

Preferred carrier selection method for selecting any available cellular

A remotely programmable radiotelephone and a remote programming unit. The radiotelephone (10) includes a receiver front end and demodulator (23), receiver signal processing circuits (30), a dual-tone, multiple-frequency converter (31), a controller (50), and a memory (51). The converter (31) converts DTMF tones into digital signals. The controller (50) monitors the output of the converter (31). If the output corresponds to a valid command then the controller (50) executes the command. Certain commands must be preceded by the user entering an access code using a control keypad (56) and by the reception of DTMF tones corresponding to a password or security code stored in the memory (51). Some commands cause telephone numbers to be stored in the memory (51) for later recall by the user. Other commands cause a number to be stored and an outgoing call to be automatically initiated. The remote programming capability allows a user's secretary to cause the radiotelephone (10) to place a call to a party specified by the user, and allows a dealer to reprogram operating parameters and features of the radiotelephone (10) without the user having to come to the dealer's place of business. The remote programming unit provides for the manual or computer-assisted programming of the radiotelephone.

Radiotelephone for automatically dialing remotely programmed number upon

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Snellville, GA, United States of America

Stephen T Hardin