RS485 Star Card Manual V14 4Feb04.doc Page 5/29
2. INTRODUCTION
GENERAL
The RS485 Star Card is designed to simplify the installation of RS485
telemetry systems.
Eight individual outputs are provided. Each output can be connected to a
single dome/receiver or up to 32 domes/receivers wired as a daisy chain.
When the domes/receivers are wired as a daisy chain, the last unit’s RS485
must be terminated and the intermediate units must be un-terminated. With
a single dome connected to each output, the RS485 must be terminated.
The Star Card can be used with either 2 wire, half duplex; or 4 wire, full
duplex systems.
It has been tested with the Panasonic FS616 multiplexer in 2 and 4 wire
modes and with the SX350 video matrix in 2 wire mode.
The Star Card can also be used with single direction RS485 links, for
example the RS485 output of DM Systems Sprite and Digital Sprite range of
multiplexers and Integral Technologies DVX range.
The Star Card is protocol independent and will work at up to 19200 baud. It
is recommended that when used with extended cable distances and/or noisy
environments 9600 baud is used to prevent control problems.
A RS232 serial output is provided via a DB9F to aid with diagnostic and
trouble shooting.
The following pages showing wiring details when used in 2 and 4 wire
systems.
