DTMF signal detection apparatus

Year	Description
1990	Invention patented by Michael E. Locke on August 30th, 1990. Abstract: Apparatus for detecting and identifying DTMF signals in connection with a voice store and forward equipment (VSF) and for preventing talk-off, whether generated by the VSF or by a user of the VSF. In particular, the apparatus for use in connection with an interface which receives an analog signal from and applies an analog signal to a telephone line, the apparatus including: (a) detection means, responsive to an analog signal received from the interface, for detecting DTMF signals in the received analog signal and for generating DTMF indication signals in response thereto; (b) means for storing a representation of the received analog signal and at least some of the DTMF indication signals and for applying at least some of the DTMF indication signals to a decision means; and (c) means for retrieving a representation of an output analog signal and a representation of output DTMF indication signals and for applying them to the decision means; wherein the decision means is means for applying the output analog signal to the interface.
Source: selected by the editor from original sources.

Invention: DTMF signal detection apparatus