Telephone call progress tones are identified by measuring the periods of their envelope cycles in the range of 20 to 200 Hertz which are due to the difference frequency of the signals used by phone company to form the call progress tones. The periods of the envelope cycles are classified, and a decision is made by a programmed microprocessor by comparing the data derived from the unknown signal to what is expected for known call progress calls of many telephone companies. In making such decision, the several period measurements are accumulated in bins, and the bin reaching the largest total is used to develop a representative period which is examined, if various other criteria are met, to identify the call. In this process, substantially regular envelope cycles are selected, and noise is rejected. An answer to the call is detected by this technique.

Telephone call progress tone and answer identification circuit

Dot printing apparatus

A printing method for use with a wire printer designed for improved printing of both higher and lower case alphabetical characters wherein additional printing points and positions are added to write better-formed characters, and especially to print improved characters having diagonally extending and curved segments.

Wire printing method

A telephone call monitoring apparatus is described for monitoring a subscriber's telephone to determine the time of day in which incoming or outgoing telephone calls are made and the duration of the calls. Additionally the apparatus determines and records the telephone number of the "called" telephone. The apparatus is responsive to the frequency, duration and pause between ring back signals placed on the telephone to determine the estimated time that the call is answered by the called telephone.

Telephone call monitoring apparatus

A device and embodied method to control access to and log telephone calls made upon a long-distance telephone network includes a telephone instrument (11), a telephone line interface (12) for selectively connecting the telephone instrument (11) to an incoming telephone line (T 1 , R 1 ) and a local telephone power supply system (23), which telephone line interface (12) provides output signals indicative of the operational status of the telephone instrument (11) and all numbers dialed on the telephone instrument (11), an access code memory (50) for storing and providing output signals indicative of a plurality of security codes authorized for utilization of the long-distance telephone network, a first (51) and second (52) log memory for storing data regarding all outgoing long-distance telephone calls made from the telephone instrument (11), and a control unit (15) which receives the output signals from the telephone line interface (12), and the access code memory (50). The control unit (15) monitors the telephone line interface (12) and upon detection of a dialed number initiating a tie-in to the long-distance telephone network directs connection of the telephone instrument (11) to the local telephone power supply system (23) and connection of the incoming telephone line (T 1 , R 1 ) to a holding load (21). The control unit (15) compares the next dialed number received to those stored in the access code memory (50) to determine the validity thereof and upon determination of a valid access code directs reconnection of the telephone instrument (11) with the incoming telephone line (T 1 , R 1 ) and further directs one of the log memories (51, 52) to record the dialed access code and telephone number.

Telephone toll call security and logging device and method

Alternating two line printing device

Telephone message data device

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Alternating two line printing device

Telephone message data device