Confidential
EPSON
TITLE
SHEET
REVISION
NO.
SHEET
NEXT
B
RP-U420 series
Specification
(STANDARD)
11
10
2.1.1.3 Interface connector terminal assignments and signal functions
Table 2.1.1 Interface Pin Assignments and Functions
Pin
No.
Signal
Name
Signal
Direction
Function
1
FG
-
Frame ground
2
TXD
Output
Transmit data
3
RXD
Input
Receive data
4
RTS
Output
Same as DTR signal (same as pin 20)
6
DSR
Input
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.
7
SG
-
Signal ground
DTR
Output
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:
Dip Switch 1-6
Status
Printer Status
ON
OFF
1) The period from power-on (or initialization of the mechanism due
to resetting through the interface) until the printer is ready to
receive data.
BUSY
BUSY
2) During the self-test.
BUSY
BUSY
3) During paper feeding using the FEED button.
----
BUSY
4) When the printer stops due to a paper-end (ESC c 4).
----
BUSY
Offline
5) During an error condition.
----
BUSY
6) When the receive buffer is full (*1).
BUSY
BUSY
20
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.
25
INIT
Output
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.
*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.