4.2.2 Connecting via the RJ-45 Connector
The RJ-45 version of Model 2084 uses an RJ-45 connector on the
RS-485 side. The RJ-45 connector is prewired for a standard TELCO
wiring environment. The signal/pin relationships are shown below in
Figure 3.
When connecting the
twisted pair cable from the 2084’s RJ-45 jack to
the RS-485 device, your cable must be connected in the manner shown
below.
MODEL 2084
RS-485 DEVICE
SIGNAL
PIN#
RS-485 SIGNAL
N/C
1
GND
*
2
N/C
3
XMT+
4
XMT A
XMT-
5
XMT B-
N/C
5
GND
*
7
N/C
8
*Connection to ground is optional
7
1
2
3
4
5
6
7
8
1 (no connection)
2 Ground
3 (no connection)
4 (TX Data + (XMT+)
5 (TX Data - (XMT-)
6 (no connection)
7 (Ground)
8 (no connection)
Figure 3. RJ-45 Twisted Pair Line Interface
4.2.3 4-WIRE CONNECTION USING TERMINAL BLOCKS
If your RS-485 application requires you to connect one pair of bare
wires to the Model 2084, 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 that the wires won't pull loose.
1. If the case is not already open, open it now by twisting it open
with a small plastic screwdriver.
2. Strip the outer insulation from the twisted pairs about one inch
from the end.
3. Strip back the insulation on each of the 2 twisted pair wires
about .25".
4. 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 same
pair of wires to XMT A and XMT B on the RS-
485 Device, respectively.
Ultimately, you will want to construct a two pair cross over cable that
makes a connection with the RS-485 device as shown below:
Model 2084
RS-485 Device
XMT+
XMT A
XMT-
XMT B
8
