User`s guide

9XTend™ RS-232/422/485 RF Modem User’s Guide
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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:
Figure 2-15. Male DB-9 to RJ-45 Adapter (yellow)
Figure 2-16. Female DB-9 to RJ-45 Adapter (green)
An XTend RS-232/422/485 RF Modem ‘Accessories Kit’ is available that includes connectors that
facilitate RS-485/422 and other serial communications. Refer to “Appendix B: Development Guide” on
page 65 for information regarding the connectors and tools included in the kit.
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.