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DCS Decoder

A soundcard decoder for DCS and CTCSS subaudible signalling


This program is a sound card decoder that will display received Digital Coded Squelch (DCS) codes and Continuous Tone Coded Squelch (CTCSS) frequencies when connected to a radio receiver.  The audio input of the computer must be connected to the discriminator of the receiver.   Connecting to the speaker or headphone output will not work because the portion of the audio spectrum that contains the DCS and CTCSS signals (below 300 Hz) is filtered out of the speaker audio.  CTCSS decoding is usually possible with speaker audio, but DCS decoding will require a discriminator input to the sound card.


  • Windows 2000 or later
  • LabView 8.5 Runtime Engine installed (see below)
  • DirectX 8.0 or later

Download & Installation

 This program was written in Labview, which means that while the program itself is relatively small, a very large runtime engine must be installed in order for the program to run.

In order for this program to run properly on a Windows computer, you must first download and install the Labview 8.5 runtime engine, which is available here.

 You must also have DirectX version 8.0 or later installed.  Windows XP and later should have this already installed, but users of earlier versions of Windows may need to upgrade.  The upgrade is available here.

 After installing the Labview runtime engine, download the installer below  and run it to install the program on your PC.

DCSdecode Installer - Current "Untested Beta" Release  

DCSdecode3 Installer - Alternate Test Version

Additional Resources

Here are some links to some very helpful DCS decoding resources: