SATO M5900RV Operation Manual page 36

4. Interface Specifications
X-On/X-Off Flow Control
X-On/X-Off flow control must be used whenever hardware (Ready/
Busy) flow control is not available or desirable. Instead of a voltage
going high/low at pin 20, control characters representing "Printer
Ready" (X-On = 11 hexadecimal) or "Printer Busy" (X-Off = 13 hexa-
decimal) are transmitted by the printer on pin 2 (Transmit Data) to
the host. In order for this method of flow control to function correctly,
the host must be capable of supporting it. X-On/X-Off operates in
a manner similar to the function of pin 20 (DTR) as previously
explained. When the printer is first switched on and goes on-line,
an X-On is sent out. In the Single Job Buffer mode, when the printer
receives a print job, it transmits an X-Off and begins printing. When
it is done printing, it transmits an X-On. In the Multi Job Buffer mode,
the printer sends an X-Off when the "Buffer Near Full" level is reached
and a X-On when the data level of the buffer drops below the "Buffer
Available" mark. When the printer is taken off-line manually, it trans-
mits an X-Off indicating it cannot accept data. When it is placed
back on line manually, it sends an X-On, indicating it is again available
for receipt of data. If an error occurs during printing (paper out,),
the printer sends nothing in the Single Job Buffer mode since the
last character transmitted was an X-Off. When the error is cleared
and the printer resumes printing, no X-On is sent until the current
job is completed and the printer is once again read to receive the
next job. If it is in the Multi Job Buffer mode, it sends an X-Off as
soon as an error condition is detected. When the error is cleared
and the printer is placed back on-line, it transmits an
X-On indicating it is again ready to accept data.
Upon switch up, if no error conditions are present, the printer will
continually send X-On characters at five millisecond intervals until
it receives a transmission from the host.
Cable Requirements
HOST INTERCONNECTION
FG
RD
TD
SG
36
Operation Manual
PRINTER
1 FG (Frame Ground)
2 TD (Transmit Data)
3 RD (Receive Data)
4 RTS (Request to Send)
5 CTS (Clear to Send)
6 DSR (Data Set Ready)
20 DTR (Data Terminal Ready)
7 SG (Signal Ground)
M5900RV