American Fibertek MRX-8885C User Manual
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The figure below identifies the specific connections for the RS422 / RS232 data connections. 
 
 
TYPICAL SYSTEM DATA CONNECTIONS 
An example of the RS422 or RS485 four wire interconnection between the 8885C 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-8885C or MRX-8885C
Please note that Data In on the MTX-8885C becomes Data Out on the MRX-8885C 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. 
