H - Electricity – 04 – M
Patent
H - Electricity
04
M
379/4
H04M 11/00 (2006.01) H04M 1/82 (2006.01) H04N 1/327 (2006.01) H04Q 1/44 (2006.01)
Patent
CA 1237209
ABSTRACT In a facsimile communication system, a device for connection to a telephone line through which unsounding and sounding a.c. call signals of different frequencies may be received, to a facsimile machine; and to a telephone set, the device being adapted to detect and discriminate between the sounding and unsounding call signals. The device comprises first binarizer means for converting any a.c. signal received over the telephone line into a signal having two binary levels; second binarizer means adapted to be unresponsive to unsounding call signals whilst converting a sounding call signal into a signal having two binary levels; and selector means connected to receive the outputs of the first and second binarizer means. The selector means, in response to detection of a predetermined frequency in the output of the second binarizer means, provides an output corresponding to the sounding call signal and, in response to receipt of the unsounding call signal by the first and second binarizer means, provides the output of the first binarizer means as the output of the selector means. The device further comprises a signal discriminating means for measuring the period of a signal output from the selector means to discriminate between a sounding and an unsounding call signal. The call signal detecting device of the invention is capable of reliably identifying signals without resorting to intricate and highly complex chip architecture. Furthermore, changes in the specifications of the signals to be detected can be accommodated by software re-programming rather than hardware changes.
478446
Borden Ladner Gervais Llp
Ricoh Company Limited
LandOfFree
Call signal detecting device does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Call signal detecting device, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Call signal detecting device will most certainly appreciate the feedback.
Profile ID: LFCA-PAI-O-1296548