Moxa Technologies EtherDevice User Manual page 34

100BaseFx Ethernet Port Connection
The concept behind the SC port and cable is quite straightforward. Suppose you are
connecting devices I and II. Contrary to electrical signals, optical signals do not require a
circuit in order to transmit data. Consequently, one of the optical lines is used to transmit
data from device I to device II, and the other optical line is used transmit data from device
II to device I, for full-duplex transmission.
All you need to remember is to connect the Tx (transmit) port of device I to the Rx (receive)
port of device II, and the Rx (receive) port of device I to the Tx (transmit) port of device II.
If you are making your own cable, we suggest labeling the two sides of the same line with
the same letter (A-to-A and B-to-B, as shown below, or A1-to-A2 and B1-to-B2).
SC-Port Pinouts
SC-Port to SC-Port Cable Wiring
3-10 MOXA EtherDevice Server User's Manual