American Fibertek MRX-8689C - Manual (Page 5)

5
The figure below identifies the specific connections for the RS485 data connections.
TYPICAL SYSTEM DATA CONNECTIONS
An example of the RS422 or RS485 four-wire interconnection between the 8689C Series unit
and the copper device to which it is attached is shown below. This illustration is based on
industry standard EIA terminology for the transmission of electronic data signals. Using this
terminology, the driver of an electronic signal is labeled TX or data out. Correspondingly, the
receiver of an electronic signal is labeled RX or data in. Not all manufactures follow standard
EIA terminology. Consult the installation instructions for your copper device if you are unsure
which two wires are the drive (data out) wires and which two wires are the receive (data in)
wires.
MTX-8689C or MRX-8689C
Please note that Data In on the MTX-8689C becomes Data Out on the MRX-8689C after going
across the fiber. The reverse flow follows the same orientation. Also note that RS485 two-wire
transmission uses only pins 6, 7, and 8 of the data terminal block.