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4.0 INSTALLATION
Once the Model 1004A is properly configured, it is ready to
connect to your system. This section tells you how to properly connect
the Model 1004A to the twisted pair and RS-232 interfaces, and how to
operate the Model 1004A.
4.1 TWISTED PAIR CONNECTION
The Model 1004A supports point-to-point or multipoint
communication over one or two twisted pair. There are two essential
requirements for installing the Model 1004A:
1.
These units work in pairs. Therefore, you must have one Model
1004A at each end of a one or two twisted pair interface. In
multipoint environments, there must be one Model 1004A at the
RS-232 host and one at each RS-232 terminal.
2.
To function properly, the Model 1004A needs one or two twisted
pair of metallic wire. These pairs must be unconditioned dry
metallic wire, between 19 and 26 AWG (the higher number gauges
may limit distance). Standard dial-up telephone circuits, or leased
circuits that run through signal equalization equipment, are not
acceptable .
For your convenience, the Model 1004A is available with several
different twisted pair interfaces: RJ-11 jack, RJ-45 jack, terminal blocks
with strain relief and dual modular jacks (for multipoint daisy-chaining).
4.1.1 TWISTED PAIR CONNECTION USING TERMINAL BLOCKS
If your application requires you to connect one or two pairs of bare
wires to the Model 1004A, you will need to open the case to access the
terminal blocks. The following instructions will tell you how to open the
case, connect the bare wires to the terminal blocks and fasten the
strain relief collar in place so the wires won't pull loose.
1. You should already have the case open for the configuration
procedure. If not, see Section 3.2.
2. Strip the outer insulation from the twisted pair(s) about one inch
from the end.
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3. Strip the insulation on each of the twisted pair wires about .25".
4. In a two pair circuit, connect one pair of wires to XMT+ and
XMT- (transmit positive and negative) on the terminal block, making
careful note of which color is positive and which color is negative.
5. Connect the other pair of wires to RCV+ and RCV- (receive
positive and negative) on the terminal block, again making careful note
of which color is positive and which color is negative.
Ultimately, you will want to construct a two pair crossover cable that
makes a connection with the two Model 1004As as shown below.
XMT+--------------------------------------------------RCV+
XMT----------------------------------------------------RCV-
G ----------------------
To Shield (Optional)
RCV+--------------------------------------------------XMT+
RCV----------------------------------------------------XMT-
6. In a single pair circuit, use only the transmit (XMT) pair as
shown below:
XMT+--------------------------------------------------XMT+
XMT----------------------------------------------------XMT-
7. If there is a shield around the telephone cable, it may be
connected to "G" on the terminal block. To avoid ground loops, we
recommend connecting the shield at the computer end only. A ground
wire is not necessary for proper operation of the Model 1004A.
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}
One Pair
G
}
One Pair
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