Copyright 2010-2017 Obihai Technology, Inc.
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Auto Answer and Intercom
(SIP/SP Only.) Intercom, sometimes (called 2-way) paging, refers to a call with the following characteristics:
1.
The called phone answers automatically, usually immediately without ringing. If the handset is on the cradle,
the speakerphone or the headset will be turned on automatically as the call is answered. Typically the answering phone
also plays a short beep to alert the called user right after answering the call. Use the option
User
Preferences
::
IncomingPageAlertTone
to control whether the phone plays a beep when auto-answering. You can
also tell the phone auto-mute when auto-answering with the option
User Preferences
::
AutoAnswerAutoMute
.
2.
The calling phone may support PTT (Push-To-Talk) in addition such that the call ends as soon as the caller
releases the respective PTT key on the calling phone. PTT does not apply to the called phone on the other hand; the
called user talks and ends the call normally just like any other call
We refrain from referring to Intercom calls as paging in this document so that it will not be confused with another
paging application called Page Groups that is based on Multicast/RTP/RTCP. We will talk more about Page Groups later
in this document.
The phone supports two methods to signal to the called device to auto-answer the call:
-
Call-Info: The phone inserts an
answer-after=0
parameter in a Call-Info header in the INVITE request
-
Alert-Info: The phone inserts
info=alert-autoanswer;delay=0
parameters in an Alert-Info header in the INVITE
request
The method to use is controlled by the parameter
ITSP Profile X
–
SIP
::
X_AutoAnswerMethod
.
Regardless of the method selected, for incoming calls, OBi1000 processes the “answer
-
after” parameter in a Call
-Info
header or the “info” and “delay” parameters in an Alert
-Info header, whichever is present in the inbound INVITE, by
automatically answering the call after ringing for the number of seconds specified in those parameters (usually 0).
When the call is automatically answered, all other current calls on the phone will be interrupted the standard way as
this is a new call added to the foreground. The auto-answer behavior can be turned off by disabling the option
Phone
Settings
–
Calling Features
::
AutoAnswerEnable
. The setting can be changed by the user from the phone under the
Preferences menu. The administrator may further define a feature key with the function
Auto Answer On/Off
to
give the user a shortcut to disable auto-answering intercom calls whenever he does not want to be interrupted. The
color of the LED reflects the current auto-answer on/off state as a visual reminder to the user. If
AutoAnswerEnable
is turned off, the intercom call will be presented to the user as a normal incoming call and will ring the phone normally.
Depending on the method selected, for outgoing calls, the OBi1000 may request the called party to auto-answer by
inserting either “answer
-
after=0” parameter in a Call
-
Info header or “info” and “delay” parameters in an Alert
-Info
header in the outbound INVITE request. This behavior can be invoked by dialing a star code that invokes the barge-in
(or bar for short) action (*96 by default) before the call and it only applies to the next immediate outgoing call.
However, the soft-switch may or may not recognize this parameter or pass it through to the called phone.
A soft-switch may have its own special way of letting a phone user invoke auto-answer feature on the called party. For
example, FreeSwitch uses the feature code 8+{extension} to signal auto-answer. For example, user can dial 81002 to
request extension 1002 to auto-answer the call.
Auto-Answer Incoming Call Based on Inbound Call Routing Rules
You can let the phone auto answer certain incoming calls based on inbound call routing rules by specifying a rule that
routes the call to ph(autoans). For example:
{someid:ph(autoans;nobeep)},{(@.4089991234):ph(antoans;delay=2)},{ph}
The autoans syntax supports two optional semi-colon separated attributes:
-
nobeep: Not to play a beep tone on answering. Default is to play the beep tone according to user preference
setting
-
delay={value in seconds}: The number of seconds to ring before auto-answering the call. Default is 0
