How to complete a loop back or range test with the Digi XTend Radio

XTend-PKG-R™        RS-232/422/485 RF Modem

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Connect Hardware
To install the modem and test its range, you need:
* 2 XTend RF Modems. The two XTend RF Modems are referred to as "Radio1" and "Radio2".
* Accessories (Loop back adapter, RS-232 cable, 2 RPSMA antennas, 2 power supplies)
* 1 Windows PC loaded with X-CTU Software

Hardware Setup
1. Set both Radio DIP Switches to RS-232, point-to-point modes. [Switches 1 and 5 are ON (up), and the remaining 4 switches are OFF (down)].
2. Connect the included RS-232 cable to the female DB-9 connector of Radio1 and the male DB-9 connector of the PC.
3. Attach the serial loop back adapter (Red adapter) to the female DB-9 connector of Radio2. (The serial loop back adapter configures Radio2 to function as a repeater by looping data back into the module for retransmission, as shown.)
4. Attach one each of the RPSMA antennas to each of the RF modems.
5. Power Radio1 & Radio2 through their respective power connectors.
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Install Software
Go to the X-CTU Software page at and launch the legacy X-CTU installer (version

If you are using the XTend Rev B product, you will need to use the XCTUNG software that is on the web site. The options below will be different for this software than it is with the Legacy XCTU.

Follow the prompts on the installation screens.
* PC Settings: Set up PC serial com ports to interface with the RF modem
• Range Test: Test RF modem's range under varying conditions
• Terminal: Read/Set RF modem parameters and monitor data communications
• Modem Configuration: Read/Set RF modem parameters

Congure Serial Port-Modem Communications
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Determine the RF Modem’s Range
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Restoring Modem Defaults (DIP Switch Method)
If the XTend Modem is not responding or cannot enter into Command Mode, try
restoring the modem to its original default parameter values.
1. Set switches 1 & 2 of the DIP Switch to their ON (up) positions, and the remaining
four switches to their OFF (down) positions.
2. Turn off the power supplying the RF modem, then on again

Other Configuration Options
Using the DIP Switch to configure the modem is one of several ways to configure
modem parameters. Other options include using the X-CTU Software Terminal and
Modem Configuration tabs, and binary programming. See the XTend-PKG-R RF Modem
User’s Guide for more information about these options.

Last updated: Jun 13, 2024

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