Customizing System Prompts
Prev Chapter 13. Managing Your Asterisk System Next

Customizing System Prompts

In keeping with the seemingly limitless flexibility of Asterisk, you can also modify the system prompts. This is very simple to explain, but generally difficult to do well.

With more than 300 system prompts in the main distribution, and an additional 600 in the asterisk-sounds add-on, if you’re contemplating customizing all of them you’d better have either a lot of money or a lot of time on your hands.

An audio engineer is also recommended to ensure that the recordings are normalized to –3 dB and that all prompts start and end at a zero-crossing point (with just the right amount of silence prepended and appended).

The Voice

If you are interested in The Voice of Asterisk, she is Allison Smith, and she can deliver customized recordings for you to use on your own system.

This is a powerful concept, as very few PBXes allow you to use the same voice in your custom recordings as is used by the system prompts.

Allison is the voice of the system prompts in both English and Spanish.

There are also prompts available in French. Montreal’s own June Wallack is the voice of the French Asterisk prompts (and also does prompts in flawless English,[144] should you want the same voice for both languages).

To find out how to get your own voice prompts, visit the Digium web site, http://www.digium.com/products/voice.

Once you have the recordings, the actual implementation is easy—simply replace the files in /var/lib/asterisk/sounds with the ones you have created.

Alternatively, you can opt to record your own prompts and place them in a folder of your choosing. When you refer to sound files with the Playback() or Background() applications, you can refer to the full pathname of the sound file, or to any subdirectory of /var/lib/asterisk/sounds/.

Note that the default sounds that come with Asterisk are delivered in format. We would not normally recommend storing them in this format (unless you have a lot of channels that will be entering the system using the GSM codec). Sure, you save some hard drive space, but the extra load on your CPU when it has to transcode all these files (not to mention the lower overall quality of the sound) makes the use of GSM undesirable, to our thinking. Use uncompressed files (such as .wav, .ulaw or .alaw) and your CPU will not have to work as hard. As an added bonus, your prompts will sound better.

Sound Recording from the Dialplan

Surprisingly, one of the easiest ways to get respectable-quality recordings is not through a PC with fancy editing software, but rather through a telephone set. There are many reasons for this, but the most important is that the telephone will tend to filter out background noise (such as white noise caused by HVAC equipment) and will record at a consistent audio level.

This little addition to your dialplan will allow you to easily create recordings, which will be placed in your system’s /tmp/ folder (from there, you can rename them and move them wherever you’d like):

exten => _66XX,1,Wait(2)
exten => _66XX,n,Record(/tmp/prompt${EXTEN:2}:wav)
exten => _66XX,n,Wait(1)
exten => _66XX,n,Playback(/tmp/prompt${EXTEN:2})
exten => _66XX,n,Wait(2)
exten => _66XX,n,Hangup()

This snippet will allow you to dial from 6600 to 6699, and it will record prompts in the /tmp/ folder using the names prompt00.wav to prompt99.wav. After you complete recording (by pressing the # key), it will play your prompt back to you and hang up.

Be sure to move your prompts out of the /tmp/ dir to the Asterisk sounds directory. To keep the dialplan readable, rename your prompt<XX> files to something more meaningful. For example:

mv /tmp/prompt00.wav /var/lib/asterisk/sounds/custom/welcome-message.wav

[144] We were going to say “accentless English”, but then we’d have to apologize to folks from the British Isles, Australia, South Africa, and who knows where else. We are not experts in languages, dialects, and such, but our ears tell us that there is a type of accent that in North America is common for professional voices. This is the accent that is common to the Pacific coast from San Diego to Seattle, and most of English-speaking Canada as well. Both June and Allison deliver English prompts in this accent, and we think it sounds great.

Prev Up Next
Running Asterisk As a Non-root User Home Music on Hold