| 摘要 |
PURPOSE:To improve the use efficiency of a public telephone line by sharing the public telephone line used for regular telephone communication and the public telephone line used for data transmission in a POS terminal. CONSTITUTION:Modem 14A and 14B are provided with priority functions and functions for discriminating from where a call is made either a telephone set or the controller of the POS terminal, encoding and transmitting it. When a telephone set 12 is busy even if modem 14A receives a call signal from a telephone set 12A and then it receives a data transmission request signal from the controller 10A of the POS terminal, it does not receive a request from the controller 10A and the call can be continued. Furthermore, modem 14A discriminates whether a caller subject is the telephone set 12A or the controller 10A by the reception of the call signal, and transmits a discrimination code to modem 14B through an exchange 16. Thus, a telephone set 12B or a controller 10B is selected, and the call or data transmission becomes possible. |
