PURPOSE: To ring a station incoming sound to a specific telephone set and to automatically stop a plurality of other telephone sets, by setting a specific number to telephone sets.
CONSTITUTION: In the state of station incoming signal reception of a plurality of telephone sets 2∼n from a master device 1, when a variable resistor VR is fully turned off, a contact vr interlocked to the VR turns on and the information is informed to a telephone set control circuit 23. A build in microcomputer of the control circuit 23 discriminates a specific number (1'-1' terminal) set at a telephone set specific number setting terminal 27, and when a specific one terminal which is predetermined is short-circuited, the control circuit 23 does not turn off an analog switch 31 and sound is produced from a speaker SP. Further, the short-circuit is done at other terminals, the analog switch 31 is turned off with the software condition with the microcomputer and the sound from the speaker SP can be stopped.
UGAKI MASAAKI
ARAKI MASATO
IWANAMI MICHIAKI
INO KAZUYOSHI
OOSHIMA SETSUO
FUJIWARA KEITAROU
NIPPON TELEGRAPH & TELEPHONE
IWATSU ELECTRIC CO LTD
MEISEI ELECTRIC CO LTD
NAKAYO TELECOMMUNICATIONS
NITSUKO LTD
TAIKO ELECTRIC WORKS LTD