5
TYPICAL SYSTEM DATA CONNECTIONS
The RS422 or RS485 four-wire interconnection between the MT-746C-SL and the copper device to
which it is attached 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. Following this standard,
the Data Out of the copper device is connected to the Data In of the MT-746C-SL. The plus terminal of
the copper device is connected to the plus terminal of the MT-746C-SL and the minus is connected to
the minus. The reverse flow of data from the MT-746C-SL to the copper device follows the same
pattern. 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.
Please note that Data In on the MT-746C-SL becomes Data Out on the MR-746C or the RR-746C after
going across the fiber. The reverse flow follows the same orientation.
CONTACT CLOSURE INPUT / OUTPUT CONNECTIONS
Contact Closure input and output connections are made via the terminal block labeled DATA 2 on the
left side of the unit. See the drawing below for proper orientation of input and output connections.
Please note that the far left pin on the connection drawing corresponds with the far left terminal block
pin located closest to the top of the unit. For example, contact closure out is the pin located closest to
the DATA 1 terminal block.
DATA CONFIGURATION SWITCHES
NOTE: This unit is shipped with Data Channel 1 in the RS485 4-wire configuration and Data
Channel 2 in the contact closure configuration.
For other configurations of data channel 1, please refer to the drawing below for changes to the default
switch settings. These configuration switches are located on the right side of the unit and can be
modified without opening the unit.
