Tamura Electric Works, Ltd.

Yoshiki Sano

Toshiharu Kinoshita

Masaaki Tsukada

Shuji Kunii

A called party response detecting apparatus of a terminal equipment includes a plurality of filter units, a determining unit, and an analyzing unit. The filter units are commonly connected to an input side and detects specific frequency components included in a plurality of signal tones coming from a telephone line. The determining unit checks the presence/absence of each output from the filter units for each fundamental period to determine a signal type on the basis of a predetermined output pattern. The analyzing unit analyzes various signal tones and a called party response on the basis of occurrences of signal type outputs during a predetermined time period of the determining unit.

Called party response detecting apparatus

A called party response detecting apparatus includes a plurality of filter units for respectively detecting natural frequency components included in a plurality of signals sent from a telephone line. The apparatus also includes switching units for switching input levels of the filter units in a plurality of steps and a continuous signal detector for detecting that a logical sum output from the filter units has continued for a predetermined interval of time. An input level control unit operates to control the switching units to set an input level at a lowest level while waiting for a signal and also to reset the input level at a predetermined level different from the lowest level when an output is obtained from one of the filter units. During this reset operation, the input level control unit decreases the input level in steps until an output is obtained from the continuous signal detector. The apparatus further includes a discriminator for determining, when the continuous signal detector continuously detects logical sum outputs from the filter units for the predetermined time, a plurality of signal tones and a called party response in accordance with the frequency pattern of the outputs from the filter units within the predetermined time.

A public telephone set that processes call charge information is provided. The set includes a register for holding a pre-determined number of digits of the dialed number and a memory in which dial control codes corresponding to the predetermined number of digits are stored in advance. Depending upon the telephone number that is dialed, a memory location is directly addressed to obtain a control code. The control code specifies a memory location in which charging information such as a charge or time increment is stored. This information is then processed to determine the appropriate charge for the number dialed.

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Kanagawa, Japan

Yoshiki Sano