Citizen Systems iDP-3550 - Manual (Page 44)

10.3 Input and Output Signals
10.3.1 Input and Output Signals
(1) RXD
This is a serial received data signal. When a framing error, overrun error, or parity error occurs, that
data is printed as "?".
(2) DTR
When this signal is Ready, write the data or a command. If written at the time of Busy, an overrun
error results, ignoring the previous data. The data can be written in the input buffer even during
printing. Busy is also issued at the time of power-on, test print, on-line, and reset.
(3) TXD
XON (11H) or XOFF (13H) is sent at XON/XOFF control. XON (11H) is sent every 3 seconds in the
STAR mode.
When a command is received, that requests the printer state and printer status, 1-byte corresponding
data is output.
(4) DSR
When this signal is a space, the data is sent from the printer side. Note that if this signal is a mark
when a request to send command is executed, the printer will wait until the signal becomes a space.
(5) FAULT
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CBM mode
When this signal is Space, a mechanical error has occurred.
- STAR mode
When this signal is Mark, a mechanical error has occurred.
(6) RESET
A signal to reset the entire printer. (Active Low)
(7) RTS
This signal is turned to Space when the printer is turned on.