| 摘要 |
PROBLEM TO BE SOLVED: To quickly detect the connection state between a personal computer and a portable telephone set via a hardware circuit and also to simplify the coding operation of an application. SOLUTION: A connection state monitoring part 6 is provided in a modem card 2 which controls the communication between a personal computer 1 and a portable telephone set 4. The part 6 detects the signal level of a 14th signal line 18 of a coupling cable 3 via a level detection circuit 19. A connection notifying circuit 13 outputs a connection notifying signal to the computer 1 when an 'H' level is detected by the circuit 19 while a connection notifying command sent from the computer 1 is set at a connection notifying F/F 12. At the same time, a data detection circuit 20 detects the presence or absence of the data on a 7th signal line 16 of the cable 3. A disconnection notifying circuit 15 outputs a disconnection notifying signal to the computer 1 when the absence of data is detected by the circuit 20 while a disconnection notifying command is set at a disconnection notifying F/F 14.
|
