7 b and sending the requested data, and step 309 b is a step of acting if the requested data is absent in step 307 b and sending regular data, and step 310 b is a step of acting if the data or command has been sent in steps 304 b, 306 b, 308 b, 309 b and starting the second data interval timer 20 b in FIG. 1. [0091] Incidentally, various kinds of the sending data are constructed of a command showi