Trane Tracer Summit Hardware And Software Installation Manual page 81

Chapter 4 UCM Communication-Link Wiring
66
3. Verify that a proper connection is made by plugging the ac adapter
into an electrical outlet and viewing the red power LED on the left
side of the modem. If the red LED does not illuminate, check the
polarity of the connection and verify that the electrical outlet is pow-
ered.
4. Connect the terminated fibers, making sure that the fiber going to
DATA REC on the next modem goes to DATA XTMR on this modem
and vice versa. Keep track of the polarity by recording the color of the
jacket on each fiber and to which connection it goes on each building.
IMPORTANT
Fiber-optic polarity is extremely important! Make sure that the fiber
connections on the fiber-optic modem are reversed for the next
modem, and then reversed again to the next modem, and so on.
5. Connect the UCM communication link and the resistor (provided with
the modem) to the modem as shown in Figure 31 on page 65. Connect
the shield at the BCU end and tape it back at the modem end. Polar-
ity of this connection is important only for Comm4 cards.
Exception: In buildings that do not have a BCU, the shield from the
communication-link wiring must be grounded on the GRD-2 terminal
between the two UCM communication-link wire terminals of the
fiber-optic modem. The shield wire must not touch either of the two
communication wires.
A typical application using twisted-pair communication wire between the
BCU and UCMs within the initial building, then connected to several
other buildings using fiber-optic modems, is shown in Figure 32 on
page 67.
BMTW-SVN01F-EN