System information

Table 11-3. Page() options
Option Description Discussion
d Enables full-duplex audio Sometimes referred to as “talkback paging,” the use of this option implies
that the equipment that receives the page has the ability to transmit
audio back at the same time as it is receiving audio. Generally, you would
not want to use this unless you had a specific need for it.
i Ignores attempts to forward the call You would normally want this option enabled.
q Does not play beep to caller (quiet mode) Normally you won’t use this, but if you have an external amplifier that
provides its own tone, you may want to set this option.
r Records the page into a file If you intended on using the same page multiple times in the future,
you could record the page and then use it again later by triggering it
using Originate() or using the A(x) option to Page().
s Dials a channel only if the device state is
NOT_INUSE
This option is likely only useful (and reliable) on SIP-bound channels,
and even so may not work if a single line is allowed multiple calls on it.
Therefore, don’t rely on this option in all cases.
A(x) Plays announcement x to all participants You could use a previously recorded file to be played over the paging
system. If you combined this with Originate() and Record(), you
could implement a delayed paging system.
n Does not play announcement simultane-
ously to caller (implies A(x))
By default the system will play the paged audio to both the caller and
the callee. If this option is enabled, the paged audio will not be played
to the caller (the person paging).
Because of how Page() works, it is very resource-intensive. We cannot stress this
enough. Carefully read on, and we’ll cover how to ensure that paging does not cause
performance problems in a production environment (which it is almost certain to do
if not designed correctly).
Places to Send Your Pages
As we stated before, Page() is in and of itself very simple. The trick is how to bring it
all together. Pages can be sent to different kinds of channels, and they all require dif-
ferent configuration.
External paging
If a public address system is installed in the building, it is common to connect the
telephone system to an external amplifier and send pages to it through a call to a chan-
nel. One way of doing this is to plug the sound card of your server into the amplifier
and send calls to the channel named Console/DSP, but this assumes that the sound
drivers on your server are working correctly and the audio levels are normalized cor-
rectly on that channel. Another, potentially simpler, and possibly more robust way to
handle external paging is to use an FXS device of some kind (such as an ATA), which
230 | Chapter 11: Parking and Paging