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volgain
Description
If enabled, and a prompt exists in /var/spool/asterisk/voicemail/recordings/callerids, then that file will
be played prior to the message, playing the file instead of saying the digits of the caller ID number.
Valid options are yes or no. Default is no.
Determines whether to play the duration of the message prior to message playback. Valid options are
yes or no. Default is yes.
Allows you to set the minimum duration to play (in minutes). For example, if you set the value to 2,
you will not be informed of the message length for messages less than 2 minutes long. Valid values
are whole numbers. Default is 2.
For applications such as Voicemail(), VoicemailMain(), and Directory(), the
voicemail context is an optional argument. If the voicemail context is not specified, then the default
is to only search the default context. With this option enabled, all contexts will be searched. This
comes with a caveat that, if enabled, the mailbox number must be unique across all contexts—
otherwise there will be a collision, and the system will not understand which mailbox to use. Valid
options are yes and no. Default is no.
Allows the user to compose and send a voicemail message from within the VoicemailMain()
application. Available as option 5 under the advanced menu. If this option is disabled, then option 5
in the advanced menu will not be prompted. Valid options are yes or no. Default is no.
Enables a notice to the user when their temporary greeting is enabled. Valid options are yes or no.
Default is no.
Sets the time zone for a voicemail user (or globally). See /usr/share/timezone for different available
time zones. Not applicable if envelope=no.
The volgain option allows you to set volume gain for voicemail messages. The value is in decibels
(dB). The sox application must be installed for this to work.
Voicemail Dialplan Integration
There are two primary dialplan applications provided by the app_voicemail.so
module in Asterisk. The first, simply named VoiceMail(), does exactly what you
would expect it to, which is to record a message in a mailbox. The second one, Voice
MailMain(), allows a user to log into a mailbox to retrieve messages.
The VoiceMail() Dialplan Application
When you want to pass a call to voicemail, you need to provide two arguments: the
mailbox (or mailboxes) in which the message should be left, and any options relating
to this, such as which greeting to play or whether to mark the message as urgent. The
structure of the VoiceMail() command is this:
VoiceMail(mailbox[@context][&mailbox[@context][&...]][,options])
The options you can pass to VoiceMail() that provide a higher level of control are
detailed in Table 8-5.
Voicemail Dialplan Integration
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Table 8-5. VoiceMail() optional arguments
Argument Purpose
b
Instructs Asterisk to play the busy greeting for the mailbox (if no busy greeting is found, the unavailable greeting
will be played).
Accepts digits to be processed by context c. If the context is not specified, it will default to the current context.
Applies the specified amount of gain (in decibels) to the recording. Only works on DAHDI channels.
Suppresses playback of instructions to the callers after playing the greeting.
Instructs Asterisk to play the unavailable greeting for the mailbox (this is the default behavior).
Indicates that this message is to be marked as urgent. The most notable effect this has is when voicemail is
stored on an IMAP server. In that case, the email will be marked as urgent. When the mailbox owner calls in to
the Asterisk voicemail system, he should also be informed that the message is urgent.
Indicates that this message is to be marked as priority.
d([c])
g(#)
s
u
U
P
The VoiceMail() application sends the caller to the specified mailbox, so that they
can leave a message. The mailbox should be specified as mailbox@context, where con
text is the name of the voicemail context (not the dialplan context). The option let‐
ters b or u can be added to request the type of greeting. If the letter b is used, the caller
will hear the mailbox owner’s busy message (if one exists). If the letter u is used, the
caller will hear the mailbox owner’s unavailable message (also assuming one exists). If
no greeting exists, the system will generate a generic message: The person at extension
<mailbox> is unavailable. Please leave a message at the tone.
In the dialplan we built in Chapter 6, we created several extensions. Consider this
simple example extension 102, which allows people to call UserB_DeskPhone:
exten => 102,1,Dial(${UserB_DeskPhone},10)
same => n,Playback(vm-nobodyavail)
same => n,Hangup()
We faked a voicemail by playing a prompt that didn’t actually do anything. Let’s
change that so the call goes to an actual mailbox instead. For now we’ll just let voice‐
mail play a generic greeting that the caller will hear. Remember, the second argument
to the Dial() application is a timeout. If the call is not answered before the timeout
expires, the call is sent to the next priority. We’ve got a 10-second timeout, and a new
priority to send the caller to voicemail after the dial timeout: