INTERFACE INFORMATION
RS-232C is the standard serial interface for data terminal equipment. The
cable connector at the printer side should be a D-subminiature Cannon or
Cinch DB-25P male connector or equivalent that conforms to EIA
standards.
SERIAL INTERFACE The table that follows shows the pin assignments commonly used by
most computers. In the table:
• “Input” denotes a signal from the computer to the printer.
• “Output” denotes a signal from the printer to the computer.
• The signal level for mark state (logical 1) is -3 V or lower; for
space state (logical 0), it is +3 V or higher.
Pin
No. Signal
Name Direction Description
1 FG − Frame Ground
2 TD Output
This pin carries information from the printer
to the computer.
3 RD Input
Received Data. This pin carries information
from the computer to the printer.
4 RTS Output
Request To Send. Spaces are sent when the
printer is ready to transmit data.
5 CTS Input Clear To Send. Spaces are sent when the
computer is ready to receive data.
6 DSR Input Data Set Ready. Spaces are sent when the
computer has been powered on and is ready
to receive or transmit data.
7 SG − Signal Ground (common return)
8 CD Input
Carrier Detect. Spaces are sent when the
computer allows the printer to receive data.
11 RC Output
Reverse Channel. This signal is used instead
of the DTR signal in the RC protocol.
Spaces are sent when the printer is ready to
receive or transmit data.
20 DTR Output Data Terminal Ready. Spaces are sent when
the printer has been powered on and is ready
to receive or transmit data.
User's Manual D-7