PURPOSE: To install a personal computer telephone without increasing the load of a PBX nor decreasing the number of terminals by using the power supply of a personal computer and the power supply of the PBX to feed a telephone set when the power supply of the personal computer is turned on and off respectively.
CONSTITUTION: A feeding switch means of a telephone set functions as a circuit which selects a DC converter 4 or a personal computer power supply part 3 to feed private telephone set 10. A feeding changeover switch 7 operates to supply a current to the telephone set 10 from the part 3 and the converter 4 when the power supply of a personal computer is turned on and off respectively. A ringer changeover means selects the converter 4 or the part 3 to feed a ringer circuit 6. Then a ringer changeover switch 8 operates to supply the power to the circuit 6 through the part 3 and the converter 4 when the power supply of the personal computer is turned on and off respectively.
KITAGUCHI MASAO
HAYASHI KIYOBUMI
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