Modem for tight coupling between a computer and a cellular telephone

• US 5,408,520 A
• Filed: 12/03/1993
• Issued: 04/18/1995
• Est. Priority Date: 11/09/1992
• Status: Expired due to Term

• Current Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Original Assignee: Compaq Computer Corporation (HP Inc.)
• Inventors: Clark, Andrew C., Baldridge, Ronald L., Jones, Randall L.
• Primary Examiner(s): Kuntz, Curtis
• Assistant Examiner(s): Chan, Jason
• Application Number:
  US08/161,925
• Time in Patent Office: 501 Days
• Field of Search: 379/93, 379/58, 379/59, 379/60, 379/61, 379/62, 379/63, 455/72, 455/38.3, 455/127, 455/343
• US Class Current: 379/93.07
• CPC Class Codes: H04M 11/06 Simultaneous speech and data transmission, e.g. telegraphic transmission over the same conductors
• CPC Class Codes: H04W 88/02 Terminal devices

Abstract

A modem which includes connections for both land lines and a cellular phone. The modem contains high and low level routines that allow it to perform standard AT commands rationally when connected to a cellular phone, and further perform additional AT commands that access cellular specific features. An applications software program in a computer connected to the modem can provide a number of options for determining whether to use the land line or the cellular phone when both are connected. First, it can default to the land line and only use the cellular phone if the land line is not available. Alternatively, it can first use the cellular phone and only use the land line if the cellular phone signal strength is not sufficient. Further, cellular file transfer operations can be aborted if the remaining battery life in the cellular phone is insufficient to reliably complete the transfer.

Claims

1. A method of transferring a file from a computer which is connected to a modem having connections to both a land line and a cellular phone powered by a battery, comprising the steps of:

determining if the battery is weak;

if the battery is not weak, transferring the file;

if the battery is weak, determining if the battery is strong enough to transfer the file in compressed format;

if the battery is not strong enough to transfer the file in compressed format, returning an ERROR condition; and

if the battery is strong enough to transfer the file in compressed format, compressing the file and transferring the compressed file.