Fred E Brooks

US Patent:

41714695, Oct 16, 1979

Filed:

Apr 27, 1978

Appl. No.:

5/900587

Inventors:

Fred E. Brooks - Orlando FL

International Classification:

H04M 344

US Classification:

179 18BA

Abstract:

An abbreviated dialing system is connected in series with a telephone line connecting one or more subscriber telephone instruments to the telephone central office. This system incorporates either a low pass or other filter which prevents the transmission of Touch Tone signals from any subscriber telephone instrument to the telephone central office, but has negligible effect on the D. C. voltage, ring signal or dial tone signal sent out over the telephone line from the central office to the subscriber telephone equipment. A filter control circuit is controlled by logic circuitry to selectively either bypass the filter or insert it in series with the telephone line. When the subscriber lifts the handset of a telephone instrument, the filter is inserted in series with the telephone line. The subscriber then transmits an abbreviated series of Touch Tone signals which are intercepted and decoded by the system's logic circuitry. A decoded Touch Tone signal is generated and transmitted by the system to the central office which rings the telephone designated by the full sequence Touch Tone signal.