Citizen Systems iDP-3550 - Manual (Page 116)

ESC "u" n
[Function] Sending the status for peripheral device
[Code] <1B>H <75>H n
[Range] n = 0
[Outline] This commands sends the status of the connector No. 3 pin.
n Connector Pin
0 Drawer kick-out connector No. 3 pin
Status Sent
Value
Bit Function
0 1
0 No. 3 pin's level “LOW” “HIGH”
1 Undefined
2 Undefined
3 Undefined
4 Undefined
5 Undefined
6 Undefined
[Caution] This command is valid only for the serial interface. If nothing is connected to the connector,
the bit 0 will be always "1". In case of DTR/DSR control, if the host cannot receive (DSR
signal has the Mark status), the printer will wait until it will be ready to receive. In case of
XON/XOFF control, only one byte will be sent without confirming the status of the DSR
signal. Note that it may take time to send the status after receiving the command.