| 摘要 |
PROBLEM TO BE SOLVED: To allow a portable information terminal equipment to make data communication through a radio channel via a slave set of a portable telephone system by providing an additional function section having a level converter matching a power supply of a driver/receiver to a power supply of the slave set. SOLUTION: A portable information terminal equipment cable 4 interconnects an additional function section 5 and a portable information terminal equipment 1. A connector 9 of a slave set side cable 8 is connected to a connector 10 of a slave set 11. Then a driver/receiver 6 being a component of the additional function section 5 power-amplifies a signal from the slave set 11 and receives the signal from the portable information terminal equipment 1. A level converter 7 being a component of the additional function section 5 converts a signal level to match the power supply of the driver/receiver 6. That is, the driver/ receiver 6 receives a signal from the slave set 11 with a high impedance and the level converter 7 converts the signal level to match the power supply of the driver/receiver 6 with respect to the power supply of the slave set 11. |
