Black Box SHM-NPR, Руководство пользователя

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10
SHM-NPR
To install a pair of these units, take these steps:
1A.
SHM-NPR (ME721 models) only:
Making sure that they are not connected to
any other device or any power source, gently pry the units open using a small
screwdriver or similar tool wedged into one of the indentations on either side
of the units’ cases. This will reveal a 5-screw terminal block mounted inside
each unit. Run 4-wire twisted-pair cable (not included) from one block to the
other as shown in Figure 3-2: one pair TX A to RX A and TX B to RX B, the
other pair RX A to TX A and RX B to TX B, and the shield (if the cable is
shielded) to the ground (middle) screw
on one end of the cable only . When you
are finished, lay the cable in the semicircle where it will emerge from the unit
so that the strain-relief prongs can pierce the cable jacket, then close the unit
back up.
CAUTION!
Under no circumstances should you attach the cable shield to the
ground screws on both ends; this could cause damaging electrical
“ground loops.”
Neither should you ever connect these units to the public switched
telephone system in any way. This could also severely damage your
equipment.
Figure 3-2. Wiring a pair of ME721 units.
XMT-
XMT+
RCV-
RCV+
RCV+
RCV-
XMT+
XMT-
G G