UC Toolkit Part 2: Audio Tools

William Bell
Vice President, Solutions and Products


I decided to do this write up after a recent job I had deploying a contact center application. I realized I had to look at some old notes on the process I used to tweak prompts. I “forgot” about certain tools I used to get the job done. Fortunately, I had good notes on the topic. However, I thought it may help others if I put my notes in this blog.

Audio Formats for Cisco Apps

There are several Cisco UC apps that allow administrators to create custom audio formats. This blog is “inspired” by my recent UCCX experience, but I thought it would be a good idea to centrally document other applications as well.

CME and CUCM Ring Tones:

  • Format: Raw PCM (no header)
  • Sample Rate: 8000 samples/second (8kHz)
  • Sample Size: 8 bit
  • Max Ring Size: 16080 samples
  • Min Ring Size: 240 samples
  • NOTES:
    • # of samples should be evenly divisible by 240
    • Ring should start/end at zero crossing

CUCM Music On Hold:

  • Standard 16-bit PCM wav format (stereo or mono)
  • 8-bit CCITT a-law or u-law (stereo or mono)
  • NOTE: in later versions of CUCM, mp3 is no longer supported
  • NOTE: CUCM takes an uploaded file and converts it to the various formats IPVMS can use.

Unity and Unity Connection:

  • 8-bit CCIT u-law (mono)
  • Sample Rate: 8000 samples/second (8kHz)
  • NOTES:
    • Media Master can be used to record or upload media
    • Greetings Administrator (CUGA) can be used to record prompts from TUI


  • 8-bit CCIT u-law (mono)
  • Sample Rate: 8000 samples/second (8kHz)
  • NOTES:
    • Can use a CRS script to create prompts (with caveats)
Excuse me, you said caveats? Yes, indeed I did. I actually got back into dusting off the audio apps I am planning to
discuss because I found a problem with using a CRS script to record prompts. When you use an IP phone to record the
prompts, there is no issue and everything works as expected. However, when you record prompts from a PSTN station
you actually hear the DTMF tone for whatever delimiter you used to have the user to signify the end of the recording. It could have just been my specific scenario (CUCM 6.1, MGCP, UCCX 5.0). In any case, something to watch out for.


Audacity is a free audio editor and recorder that has been around since 2000. It runs on Windows, Mac OS X, and GNU/Linux platforms. Audacity has a pretty robust set of features for a free application. You can see a list of features here. The latest release is available on sourceforge (Audacity Download). 

Using Audacity to read Ring Tone Files:

You can use Audacity to import ring tone files from CUCM. You need to download the ring tone file to your desktop (you can use a TFTP client to get the file). Once down loaded you can go to File>Import>Raw Data (Audacity 1.3 beta on Mac OS X) or Project>Import Raw Data (Audacity 1.2.6 on Windows).

When importing a file, you have to specify the parameters that Audacity should use to read the file. Use the following:

  • Encoding: U-Law
  • Byte order: Big-endian
  • Channels: 1 Channel (Mono)
  • Start offset: 0
  • Amount to import: 100%
  • Sample rate: 8000 Hz

You can now work with the file.

William Bell is the Collaboration Practice Lead for Chesapeake NetCraftsmen. Bill has over 10 years of experience in the IT industry with a focus on communication and collaboration technologies. In addition to blogging on the NetCraftsmen site, Bill also maintains the UC Guerrilla blog: http://ucguerrilla.com. You can follow Bill on Twitter: @ucguerrilla

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