RS-232 to Wireless Converter Modem Guide


The NCD RS-232 Wireless Modem is designed to act as a RS-232 communications interface between NCD Wireless Sensors and computers or embedded systems equipped with a RS-232 communications port.  This device acts as a 2-Way converter, making it possible to read and configure sensor settings. 

The wireless range of the Wireless RS-232 Modem may be up to 2 Miles when using a 900MHz communications technology.  Shorter ranges should be expected for indoor applications and other frequencies.  The 900MHz module is also rated for use up to 28 Miles away when working with high-gain antennas (please contact for a antenna suggestion).

NCD Wireless modems are also fully compatible with NCD endNode devices, allowing for full 2-way communications for both monitoring and device control applications.  This device consists of a RS-232 interface and a wireless communications module, equipped with either 900MHz, 868MHz, or 2.4GHz communication modules.  The NCD RS-232 wireless modem also supports’s X-CTU software, used for advanced configuration settings and firmware upgrades of Digi wireless modules.

Using the NCD RS-232 Modem

Using the NCD Wireless to RS-232 Modem is very easy, but there are a few important settings that need to be disclosed.

  • The Default Communication Baud Rate is 115.2K Baud, Other Baud Rates will be Ignored
  • All NCD Enterprise Devices use 128-Bit AES Encryption by Default, Insecure Devices will Ignore All Communications
  • All NCD Enterprise Devices use the Same Default 128-Bit AES Encryption Key, Devices with Different Keys will be Ignored
  • You May Use X-CTU to Set the Wireless Encryption Keys, but Other Settings in X-CTU Should Not be Altered

Receiving Sensor Data

To receive data from NCD Wireless sensors, simply open the COM port associated with the Modem of your computer and run any terminal program capable of displaying raw data bytes.  When a sensor sends a broadcast, the modem will receive the data and send it out the COM port.  The default COM port settings are 115.2K Baud, 8 Data Bits, 1 Stop Bit, No Parity.

Use Alpha Station Software if you would like to convert incoming data to meaningful values with a user interface.


This device includes a RP-SMA Antenna Rated for use at 900MHz, 868MHz, or 2.4GHz, depending on the version purchased.  High-Gain antennas may be available for longer range applications, please contact for additional information regarding compatible antennas.  The included antenna prevents potential operation of this device outside FCC legal limits.  This device may not be legal for use in some areas, please consult your local laws prior to purchase.

Power Requirements

This device includes a DB9 RS-232 Extension Cable, used to Connect the Wireless RS-232 Modem to a standard RS-232 Port of a Computer or Embedded System.  We strongly advise using the included cable.  Incorrect cable wiring, including Null-Modem cables, should not be used with this device.

RS-232 Connection Requirements

The NCD RS-232 Wireless Modem requires a +12V DC Power Supply, Which is Included.  This Wireless Modem will not function without power.  Should you choose to use your own power supply, the Modem utilizes a 2.1mm Barrel Jack with a Center Positive connection.  This device is expecting +12VDC with a Minimum Power Rating of 150mA.