AudioCodes Mediant 2000, User Manual

Page: 377 / 418

Version 5.6 377 November 2008
SIP User's Manual 7. IP Telephony Capabilities
7.15 Working with Supplementary Services
The device supports the following supplementary services:
„ Call Hold and Retrieve (refer to ''Call Hold and Retrieve'' on page 377 ).
„ Call Transfer (refer to ''Call Transfer'' on page 377 ).
„ Call Forward: when a callRerouting IE is received in a FACILITY message in response
to an outgoing SETUP message, the device sends a 3xx response to the IP side,
including the callRerouting destination number - only applicable to QSIG protocol
„ Call Waiting
The device SIP users are only required to enable the Hold and Transfer features. By
default, the Call Forward (supporting 30x redirecting responses) and Call Waiting (receipt of
182 response) features are enabled.
Notes:
•
All call participants must support the specific supplementary service that
is used.
•
When working with certain application servers (such as BroadSoft’s
BroadWorks) in client server mode (the application server controls all
supplementary services and keypad features by itself), the device's
supplementary services must be disabled.
7.15.1 Call Hold and Retrieve
Hold and Retrieve:
„ The party that initiates the hold is called the
holding
party; the other party is called the
held
party. The device can't initiate Call Hold, but it can respond to hold requests and
as such, it's a help party.
„ After a successful Hold, the holding party hears a Dial tone (HELD_TONE defined in
the device's Call Progress Tones file).
„ After a successful retrieve, the voice is connected again.
„ The hold and retrieve functionalities are implemented by Re-INVITE messages. The IP
address 0.0.0.0 as the connection IP address or the string ‘a=inactive’ in the received
Re-INVITE SDP cause the device to enter Hold state and to play the Held tone
(configured in the device) to the PBX/PSTN. If the string ‘a=sendonly’ is received in the
SDP message, the device stops sending RTP packets, but continues to listen to the
incoming RTP packets. Usually, the remote party plays, in this scenario, Music on Hold
(MOH) and the device forwards the MOH to the held party.
You can also configure the device to keep a call on-hold for a user-defined time after which
the call is disconnected, using the
ini
file parameter HeldTimeout (refer to ''Supplementary
Services'' on page 159 ).