iDP3420/3421/3423 User’sMa nual
34 CITIZEN
(7) RTS
This signal is turned to Sp ace when the printer is turned on.
(8) RCH
When the printer is ready to receive, this signal is turned to Space. This signal line is the same as
DTR.
(9) mTXD
TXD signal for the diode ga te.
(10) mRXD
RXD signal for the di ode gate.
(11) FG
Thisis a Frame Ground signal.
(12) GND
This is a common ground on the circuit.