Asterisk has a wonderful, built-in ability to record calls. No additional software is required to make this happen. When Asterisk records a call, both sides of the call are recorded and written out to a file for playback on a computer. Call recording is often performed in call centers to ensure call quality, or to keep calls for later review, should the need arise. Asterisk provides the ability to record all of the calls, or to selectively record calls.

In this article, we will look the following:

 
• General recording options
• Recording calls to extensions
• Recording calls to queues
• Recording calls to conferences
• Maintaining call recordings

Before enabling call recording for your PBX, make sure that you are aware of the legalities surrounding call recordings and privacy laws. Call recordings are prohibited in certain places, unless the caller is told that the call will be recorded. For example, in the state of California all of the parties on the call must consent to the call being recorded before it begins. Playing back a message stating that the call is being recorded prior to the call being answered is considered a valid form of consent.

Recording formats

FreePBX allows calls to be recorded in the following formats:

• WAV
• WAV49
• ULAW
• ALAW
• SLN
• GSM

Each format has its own ratio of file size to recording quality, and certain formats will not play on all of the computers. A comparison between all of the  available formats is as follows: