User`s guide

Communications 9
Communications
This terminal is equipped with three ports. The two serial ports
are intended for connecting to either a host/modem or a serial
printer. The remaining port is a Centronics-compatible printer
port. The port you use as the printer port depends on whether
you have a serial or a parallel interface to the printer.
The first host/printer serial port (SES1-EIA) can communicate
with your computer or printer at a baud rate of 110 to 134,400
baud (bits per second). The second host/printer serial port
(SES2-AUX) can communicate at speeds from 110 baud to 38,400
baud. Either port can be used to connect to a host
computer/modem or serial printer.
You have the choice of using either the second serial port or the
parallel printer port as your printer interface. Refer to the
following sections for further information on these ports.
Receive Flow Control
Because devices can receive data faster than they can process it,
data flow control (selectable in the PORTS menu of Setup)
should be used to prevent data loss. Software flow control relies
on the Xon and Xoff characters (“g” and “e” characters in Scan
Code key mode) to indicate when the terminal is able or unable
to store further data. The Xon signal transmits the DC1
character (11h) and the Xoff signal transmits DC3 (13h).
When “EIA (or Aux) Rcv” in the Setup menu for PORTS is
“Xon-Xoff,” the terminal issues an Xoff character, indicating to
the host that it should stop transmitting data. The terminal will
then continue to process data until its receive buffer is empty. It
will then issue an Xon character to the host, indicating that it
can resume sending data to the terminal.