User guide

Appendix B: Audio/Serial Ports: Operation & Multi-Port Configuration 35
Audio/Serial Interface Setup and Operation
SDRK/6A and SDRK/6AD only
Serial Port Configuration
No setting up or user adjustments are required.
In the Audio/Serial extender family, the serial port is wired as DTE - the same
as that on a PC. To connect a serial printer or other DTE (rather than DCE
device) to the Remote Unit, you will need a Null-Modem crossover cable
between the Remote Unit and the printer. Select Xon/Xoff software flow
control on the printer and PC.
A serial touch screen may be plugged directly into the Remote Unit.
Please note that on dual access Local Hubs, the serial link is always active.
Handling Multiple Serial Devices
The extender’s serial interface transmits/receives six signals (3 signals in each
direction).
Normally, four of these signals are used for hardware handshaking (in addition
to TX & RX). However, because each handshaking line can support signals up
to 19,200 Baud it is possible to configure the serial interface to handle up to
three simple 2-wire (Tx/Rx only) serial links.
To do this, you will need to construct a custom breakout cable. Please contact
Technical Support for further information.