Citizen CBM-270 user manual Input and Output Signals

CBM-270 User’s Manual

7.3Input and Output Signals

7.3.1Input and Output Signals

(1)RXD

Serial received data signal. If a framing error, overrun error, or parity error takes place, the relevant data will be printed as "?".

(2)DTR

Write the data or a command when this signal is Ready. If you write at Busy, the previous data will be ignored, resulting in an overrun error. The data can be written in the input buffer even during printing. Busy is also issued at power-on, during test printing, at on- line, or at reset.

(3)TXD

If the remaining capacity of the input buffer comes to 128 bytes or less while receiving the data, DC3(13H) will be output as a data not receivable signal. If the remaining capacity comes to 256 bytes or more, DC1(11H) will be output to the host side as a data receivable signal.

When sending the status information, it is confirmed that DSR is a space prior to sending the data, if DTR/DSR control has been selected. If DTR/DSR control has not been selected, the data will be sent, ignoring the DSR signal.

(4)FG

Ground for the case

(5)GND

Common ground for the circuits

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