FireBrick Call Recording: Difference between revisions

* a C application, ''voip-answer'', which acts as a SIP endpoint and handles the call recording; and

from: https://github.com/revk/voip-answer

==Setting up ''voip-answer''==

The ''voip-answer'' application comes with a Makefile, but I found I needed to make a couple of tweaks to get it to work:

svn export --force -r 28442 svn://changeless.aa.net.uk/fb6000/trunk/apps/siptools.c $@''

touch $@ # SVN sets the timestamp to the committed one (which triggers "building" every time)''

2.) depending on your version of voip-answer.c, you may need to set the email address parameter (i.e. the ''from'' address). Change line 803 from:

sprintf (temp, "sip:%c@voiceless.aa.net.uk", done);

(As of 9 August 2018, this has been replaced in voip-answer.c with "sip:%s%.*s", so no modification is necessary.)

char template[] = "/tmp/voip-answer-XXXXXX";

(If you do not have it installed already, you might need to install libpopt-dev.)

So, for example, if you wanted to run ''voip-answer'' with a call recording script at ''/voipuser/voip-answer/python/voip-rec-email/voip_rec_email.py'', serving wav files for announcements from ''/voipuser/voip-answer/sounds/'', you would run it with:

./voip-answer -r /voipuser/voip-answer/python/voip-rec-email/voip_rec_email.py -d /voipuser/voip-answer/sounds/

If you want to run it as a background process (which you probably do...), append an ampersand:

./voip-answer -r /voipuser/voip-answer/python/voip-rec-email/voip_rec_email.py -d /voipuser/voip-answer/sounds/ &

As well as acting as a SIP endpoint for recording calls, ''voip-answer'' doubles as a playback system, which you can use to play announcements.

* 8000 Hz sample rate

You can easily use Audacity to create suitable files; just remember to set the sample rate to 8000 Hz, and to set the track to mono only, first.

If, when you play the files back through ''voip-answer'', they sound distorted, chances are you have either got the sample rate wrong, or else accidentally recorded them in stereo.

If you have a recording at a different sample rate, using Audacity, change the project's sample rate to 8000, then change the recording's sample rate to 8000, and then use the "Change Speed" effect on the recording — if the original rate was 44100 Hz, apply a speed multiple of 5.50.

== Hosting the announcement / playback files ==

Files to be played back can be put in any directory readable by ''voip-answer''. You tell it which directory to look in by using the ''directory'' or ''-d'' switch. For example:

./voip-answer -d /voipuser/voip-answer/sounds/

== Triggering the announcement / playback files ==

You send traffic to the announcement / playback files by configuring a new extension on the FireBrick, and giving it a SIP URI containing the relevant parameters.

The parameters you can choose from are:

=== Prefixes (in this order) ===

XXX= This call is not to be answered, but call progress. XXX is final status

= This call is not to be answered, but call progress. End with constant ringing

- Add a ring, may be repeated

! Add a SIT, may be repeated

N* The playback sequence is to be repeated N times

You can download aai.wav and sit.wav [https://support.aa.net.uk/images/9/98/Firebrick_tones.zip here].

=== Filenames ===

Following the prefix are dot separated filenames, assumed to be wav files, to play.

A filename can have a ? after it followed by another filename. This skips the second file if the first exists.

Each dot is also a small time delay, so several dots can be used for a pause.

=== Suffixes, one applies ===

=filename Record to file

* Silence

# Refer to #

So if you wanted two rings, followed by playback of a file called "onholiday.wav", you would specify the following SIP URI:

''--onholiday@hostname/address''

=Pre-call announcements (e.g. "this call will be recorded")=

You can combine these features with the REFER function ("#"), to create an extension which will first play back an announcement (such as "This call will be recorded"), before referring the call to your chosen destination.

You do not need to do anything with the voip-answer.c script (other than make sure your chosen recordings are in the right place).

Configure your FireBrick:

# As at 10 August 2018, make sure you have alphas enabled, and have at least alpha V1.48.123

# Create a new telephone extension (or amend an existing one)

# Give it the username "Voicemail" and do not give it a password

# Add the URI: <your-pre-call-sound-file>#<extension you want to refer to>@hostname/address

So if you wanted to first play an announcement of called "callsarerecorded.wav", followed by a refer to your extension or hunt group number 500, you would use:

callsarerecorded#500@hostname/address