Telephony Capabilities; Working With Supplementary Services; Call Hold And Retrieve; Initiating Hold/Retrieve - AudioCodes Mediant 1000 User Manual

SIP User's Manual
9

Telephony Capabilities

9.1

Working with Supplementary Services

The Mediant 1000 gateway supports the following supplementary services:
Call Hold and Retrieve; refer to Section 9.1.1.
Consultation / Alternate; refer to Section
Call Transfer (Refer + Replaces); refer to Section 9.1.3.
Call Forward (3xx Redirect Responses); refer to Section 9.1.4.
Call Waiting (182 Queued Response); refer to Section 9.1.5.
Message Waiting Indication (MWI); refer to Section 9.1.6.
To activate these supplementary services (Hold, Transfer, Forward, Waiting and MWI) on
the Mediant 1000 gateway, enable each service's corresponding parameter either from the
Web Interface or via the ini file. Note that all call participants must support the specific used
method.
Note:
9.1.1

Call Hold and Retrieve

9.1.1.1

Initiating Hold/Retrieve

Active calls can be put on-hold by pressing the phone's hook-flash button.
The party that initiates the hold is called the holding party; the other party is called the
held party.
After a successful Hold, the holding party hears a Dial Tone (HELD_TONE, defined in
gateway's Call Progress Tones file).
Call retrieve can be performed only by the holding party while the call is held and
active.
The holding party performs the retrieve by pressing the hook-flash.
After a successful retrieve, voice is connected again.
The hold and retrieve functionalities are implemented by REINVITE messages. The IP
address 0.0.0.0 as the connection IP address or the string 'a=inactive' in the received
REINVITE SDP cause the gateway to enter Hold state and to play held tone
(configured in the gateway) to the PBX/PSTN. If the string 'a=recvonly' is received in
the SDP message, the gateway 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 Mediant 1000 forwards the MOH to the held party
9.1.1.2

Receiving Hold / Retrieve

When an active call receives REINVITE message with either the IP address 0.0.0.0 or
the 'inactive' string in SDP, the gateway stops sending RTP and plays a local Held
Tone.
When an active call receives REINVITE message with 'sendonly' string in SDP, the
gateway stops sending RTP and listens to the remote party. In this mode, it is
expected that on-hold music (or any other hold tone) is to be played (over IP) by the
remote party.
Version 5.0
When working with application servers (such as BroadSoft's BroadWorks)
in client server mode (the application server controls all supplementary
services and keypad features by itself), the gateway's supplementary
services must be disabled.
9.1.2.
267
9. Telephony Capabilities
December 2006