
Documentation is subject to change without notice. See
http://www.mircom.com/tx3 for the latest version of this document.
Mircom technical support: 1-888-647-2665
1. Make sure that the power is o (the On/O Switches
on the card access controllers are o).
2. Connect the MD-990 load power supply wires to the 16
VAC IN terminals on the rst card access controller.
3. Connect the other card access controllers to the rst
one in parallel (daisy chain).
4. Connect the building power supply wires to the MD-
990 line terminal screws as shown in Figure 5.
5. Connect the other end of the building power supply
wires the line voltage terminals.
The power supply enclosure is shown in Figure 4 (for clarity
the power supply is not shown).
1. Find a suitable location for the power supply enclosure,
such as over a wall stud.
2. Using the power supply enclosure as a template,
mark the back mounting hole locations as indicated
in Figure 4. Ensure that at least one side is over a wall
stud.
3. Remove the power supply enclosure and place two
screws halfway into the top marked hole locations and
wall stud.
4. Place the power supply enclosure onto the two screws.
5. Screw two screws into the bottom holes.
6. Tighten all four screws into place.
The enclosure can also be mounted directly onto the drywall
using anchors.
Figure 5: Terminal block wiring
Figure 3: Chassis ground
CONNECT AC POWER
To building
power
To 16 VAC IN
on card access controller
{
{
MOUNT THE MD-990
POWER SUPPLY
GROUND
1. Make sure that the power is o.
2. Attach one end of the supplied 14 AWG wire to the
chassis ground terminal and connect the other end to
the site ground (water pipe).
Chassis
Ground
Figure 4: Power supply enclosure
LT-1182 rev 1.2 Page 5 of 6
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TX3-BBCX-4W Assembly