DTMF download technique for digital telephone devices

Year	Description
1998	Invention patented by Syed S. Ali and Charles W. Berthoud on April 9th, 1998. Abstract: The present invention utilizes common hardware and software routines already present in most digital telephone devices, e.g., a DTMF detector; to download data over a telephone line to a digital telephone device. Each symbol of a numeric system, e.g., a hexadecimal system, used to represent the data is associated with a DTMF tone pair. The DTMF tone pair is downloaded from a data source such as a manufacturer of the digital telephone device, to the digital telephone device using a telephone line. Other tones may be used to provide control signals between the data source and the digital telephone device. Thus, using common and inexpensive routines in a typical digital telephone device, the expense of a modem or other conventional data communication device is not necessary to receive data.
Source: selected by the editor from original sources.

Invention: DTMF download technique for digital telephone devices