Epson RP-U420 Series Specification page 18

Confidential
2.1.1.3 Interface connector terminal assignments and signal functions
Pin Signal Signal
No. Name Direction
1 FG -
2 TXD Output
3 RXD Input
4 RTS Output
6 DSR Input
7 SG -
20 DTR Output
Offline 1) The period from power-on (or initialization of the mechanism due
2) During the self-test.
3) During paper feeding using the FEED button.
4) When the printer stops due to a paper-end ( ESC c 4 ).
5) During an error condition.
6) When the receive buffer is full (*1).
25 INIT Output
*1 • The period from when the remaining space in the receive buffer drops to 256 bytes until it
increases to 1000 bytes is called the "buffer full state."
• Data received when the remaining space in the receive buffer is zero bytes is ignored.
EPSON
Table 2.1.1 Interface Pin Assignments and Functions
Function
Frame ground
Transmit data
Receive data
Same as DTR signal (same as pin 20)
Indicates whether the host can receive data. SPACE indicates that the
host can receive data, and MARK indicates that the host cannot receive
data. When DTR/DSR control is selected, the printer transmits data after
checking this signal. When XON/XOFF control is selected, the printer
does not check this signal. Changing the DIP switch setting enables this
signal to be used as a reset signal for the printer. The printer is reset
when the signal remains MARK for 1 ms or more.
Signal ground
1) When DTR/DSR control is selected, this signal indicates whether the
printer is BUSY. SPACE indicates that the printer is READY to receive
data, and MARK indicates that the printer is BUSY. DIP switch 1-6
switches conditions for BUSY. The BUSY (MARK) condition is
changed using DIP switch 1-6 as follows:
Printer Status
to resetting through the interface) until the printer is ready to
receive data.
2) When XON/XOFF control is selected, this signal indicates whether the
printer is properly connected and is ready to receive data. SPACE
indicates that the printer is properly connected and is ready to receive
data. This signal is always SPACE except during the following periods:
• From power-on until the printer is ready to receive data.
• During the self-test.
Changing the DIP switch setting enables this signal to be used as a reset
signal for the printer. The printer is reset when the signal remains
SPACE for 1 ms or more.
TITLE
RP-U420 series
Specification
(STANDARD)
Dip Switch 1-6
Status
SHEET
NO.
REVISION
NEXT
B
11
ON OFF
BUSY BUSY
BUSY BUSY
---- BUSY
---- BUSY
---- BUSY
BUSY BUSY
SHEET
10