| 摘要 |
PURPOSE:To simplify the transfer of signals between different code systems, by connecting a block containing a code system converting part and a code system discriminating part to a keyboard of a system which performs a bidirectional transmission. CONSTITUTION:A connector 20 is connected to a keyboard of a terminal device which can transmit data in both directions. Pins P1-P3 are connected to an earth line as well as to power supply lines of -5V and -12V, respectively. A level 0 or 1 is applied to a pin P4 from the keyboard of the main body in accordance with the type of the keyboard. The level is set at 1 with 7 bits/words and set at 0 with a special keyboard of 12 bits, respectively, for example. A pin P5 functions as an input terminal, and a pin P6 is set at 0 with 75B transmission rate and at 1 with 1,200B, respectively. Whether or not the bit code is converted 23 is switched 24 by discriminating 21 the voltage of the P4. Then the voltage of the P6 is discriminated 22 to vary the frequency of a clock 25, and the code is discriminated at a code discriminated part 26. In such a way, the data can be transferred simply between different code systems. |
