Patent ID: 6028892
Filing Date: 2000-02-22
Classification: H04W

Abstract:
A data communication system between first and second data devices, comprising:(a) a mobile telephone unit comprising a first modem connected to the first data device;(b) a base station in radio communication with the mobile telephone unit, the base station maintaining a voice channel for carrying voice signals between the mobile telephone unit and a dialed or dialing unit; and(c) a second modem connected to a point along the voice channel, the second modem being in data communication with the first modem, the first and second modems sending signals to and receiving signals from each other in bursts comprising a synchronization word being a 16-bit code and having a variable error threshold, and said synchronization word for enabling one of said modems that is receiving said burst to differentiate the burst from the voice signals carried over the voice channel, the voice signals being muted during each burst, and the second modem being connected to the second data device, whereby the first and second modems provide a data channel between the first and second data devices seemingly concurrently, and with minimal interference, with the voice signals that are being carried over the voice channel and without requiring modifications to the base station.