Patton electronic 2085 User Manual

Page 7

4.1.3 4-WIRE CONNECTION USING TERMINAL BLOCKS

If your RS-485 application requires you to connect two pairs of bare

wires to the Model 2085, 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. You should already have the case open for the configuration

procedure. If not, open the case according to the diagram in Section
3.2.

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

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 cross over cable that

makes a connection with the RS-485 device as shown below:

Model 2085

RS-485 Device

XMT+.............................RCV+
XMT-..............................RCV-

RCV+.............................XMT+
RCV-..............................XMT-

6. If there is a shield around the telephone cable, it may be

connected to "G" on the terminal block. We recommend connecting the
shield at the computer end only to avoid ground loops. A ground wire is

not necessary

for proper operation of the Model 2085.

7. When you finish connecting the wires to the terminal block, the

assembly should resemble the diagram below:

8. Place the 2 halves of the strain relief assembly on either side of

the telephone wire and press together very lightly. Slide the assembly
so that it is about 2 inches from the terminal posts and press together
firmly. If your cable diameter is too small or too large for our strain
relief, please contact our technical support. We have strain relief
assemblies to accommodate most cable diameters.

(continued)

+RCV- G -XMT+