9XTend
‐
NEMA™
RS
‐
232/485
RF
Modem
–
Product
Manual
v2.x4x
[2007.01.04]
©
2007
MaxStream,
Inc.,
Confidential
&
Proprietary
‐
All
Rights
Reserved
12
Figure
2
‐
14. XTend
RF
Modem
in
an
RS
‐
422
environment
RS-485/422 Connection Guidelines
The RS-485/422 protocol provides a solution for wired communications that can tolerate high
noise and push signals over long cable lengths. RS-485/422 signals can communicate as far as
4000 feet (1200 m). RS-232 signals are suitable for cable distances up to 100 feet (30.5 m).
RS-485 offers multi-drop capability in which up to 32 nodes can be connected. The RS-422 proto-
col is used for point-to-point communications.
Suggestions for integrating the XTend RF Modem with the RS-485/422 protocol:
2.3.3. Adapters
Accessories packages are available that include adapters that facilitate the following functions:
• Performing Range Tests
• Testing Cables
• Connecting to other RS-232 DCE and DTE devices
• Connecting to terminal blocks or RJ-45 (for RS-485/422 devices)
RS-485/422 Adapters
Figure
2
‐
15. Male
DB
‐
9
to
RJ
‐
45
Adapter
(yellow)
Figure
2
‐
16. Female
DB
‐
9
to
RJ
‐
45
Adapter
(green)
1.
When using Ethernet twisted pair cabling: Select wires so that T+ and T- are connected to
each wire in a twisted pair. Likewise, select wires so that R+ and R- are connected to a
twisted pair. (For example, tie the green and white/green wires to T+ and T-.)
2.
For straight-through Ethernet cable (not cross-over cable) - The following wiring pattern
works well: Pin3 to T+, Pin4 to R+, Pin5 to R-, Pin6 to T-
3.
Note that the connecting cable only requires 4 wires (even though there are 8 wires).
4.
When using phone cabling (RJ-11) - Pin2 in the cable maps to Pin3 on opposite end of
cable and Pin1 maps to Pin4 respectively.
