Citizen Systems iDP3420 - Manual (Page 49)

iDP3420/3421/3423 User’s Manual
33 CITIZEN
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
As data is received, the remaining capacity of the printer’s input buffer decreases.
When it becomes less than 128(10) bytes, a DC3(13H)(Data reception disable signal) is output to the
host computer. On the other hand, when the remaining capacity of the input buffer increases to
256(20) or more bytes, a DC1(11H)(Data reception enable signal) is output to the host computer.
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.
Note: The values in ( ) are for when the 256 bytes of the input buffer is selected by
DIP switches.
(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
1
CBM mode
When this signal is Space, a mechanical error has occurred.
2
Star mode
When this signal is Mark, a mechanical error has occurred.
(6) RESET
A signal to reset the entire printer. (Negative logic)