DATA-LINC GROUP
6
PN 161-10003-002B
rev 8/03
MDL500 User Guide
Jumper Settings
There are several configuration options that can be selected by jumpers as described below. The jumper pins are internal and
are identified by lettering on the circuit board. Jumper pins are accessed by removing the four retaining screws on the top
cover of the enclosure and removing the cover.
Note: The header position locations are described with the MDL board oriented with the LED’s to the left and the
connectors to the right.
DCE and DTE Settings
Both the MDL500 Master and Remote units are configured at the factory as DCE (Data Communication Equipment) for
connection to DTE (Data Terminal Equipment). A PC, PLC or Multiplexer is usually configured as DTE. If either the Master or
Remote DTE/DCE must be changed, this is accomplished by moving the jumpers on blocks “P1” and “P2” which are located
directly behind the DB25 RS232 connector on the rear panel. For example, as delivered, the Master unit P1 and P2 jumpers
are both set in the B-C position (DCE setting). To change to a DTE, move both jumpers to the A-B position. In DTE, data
into the DB25 will be on pin 3 and data out on pin 2.
Transmitter Output Level
The MDL500 allows the selection of either Normal or High Power (HP) transmitter output. The High Power output has six
times greater peak-to-peak transmitted signal and provides correspondingly greater signal to noise ratio. High Power
transmitter operation is generally preferred in applications involving sliding contacts or in very noisy EMI environments.
However, caution is advised in some cases since High Power carrier signals will result in more cross-talk to adjacent
conductors.
The jumper to select Normal or High Power is located at position TP2. High Power is selected when the jumper is positioned
center to left; Normal output is selected with center to right. When using the HP setting, the receiver gain should be set to
low. (See Receiver Gain below.) The factory setting is Normal, center to right. This header is positioned slightly below the
TOKO Coil marked “T5.”
Receiver Gain
The MDL500 incorporates a receiver amplifier on the circuit board. This amplifier has low, normal and high gain settings
configured by a “T” shaped pin block near the center of the circuit board with pins marked “G1,” “G2” and “G3” (the leg of the
“T”). G1/G2 is the high gain setting; G2, the normal medium gain; and G3/G2, the low gain. The units are delivered from the
factory set at normal gain because the transmitter has been factory set at normal output. The low gain setting should be
used on the receiver whenever the high power transmitter option is selected on the transmitter to avoid onboard cross-talk.
