5
TYPICAL SYSTEM DATA CONNECTIONS
The RS422 or RS485 four-wire interconnection between the MT-945SL 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-945SL. The plus terminal of
the copper device is connected to the plus terminal of the MT-945SL and the minus is connected to the
minus. The reverse flow of data from the MT-945SL 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-945SL becomes Data Out on the MR-945SL or the RR-945SL after
going across the fiber. The reverse flow follows the same orientation.
DATA CONFIGURATION SWITCHES
NOTE: This unit is shipped with Data Channel 1 and Data Channel 2 in the RS485 4-wire
configuration.
For other configurations of data channel 1 or data channel 2, 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.
DATA TERMINATION AND BIAS SWITCHES
NOTE: This unit is shipped with data terminations off and data bias off for Data Channel 1 and
Data Channel 2. For other configurations, please refer to the DATA TERMINATION AND BIAS
section on the next page for changes to the default switch settings.
