| 摘要 |
PROBLEM TO BE SOLVED: To eliminate the output of photodetection signals, even if infrared rays, etc., are inputted to an infrared communication port, other than those kept under communication and to prevent communication errors caused by the disturbance noises by selecting a single infrared communication port to perform the infrared communication, when the number of infrared communication ports is increased. SOLUTION: When an optional paper feed cassette is not extended, a controller 50 outputs high selection signals (a) and (b). Then a switching control signal (c) outputted from a logical operation means 43 is set at a high level with other control signals (d) to (f) which are to be set at low levels respectively. Meanwhile, a switching means 41A is turned on, and the photodetection signal of an infrared communication port 10A is processed by the controller 50 and printed out. In an extension mode of the option paper feed cassette, an infrared communication port 10D is selected by a selector 60. Thus, only the switching signal (f) is set at a high level by the controller 50. Then only a switching means 41D is turned on, and only the photodetection signal of the port 10D is outputted to the controller 50. At the same time, the controller 50 outputs a display control signal to display the selected port. |
