Call Hold And Retrieve; Call Transfer - AudioCodes Mediant 3000 User Manual

SIP User's Manual

18.5.2.1 Call Hold and Retrieve

Call 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 held 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 HeldTimeout parameter.

18.5.2.2 Call Transfer

The device supports the following call transfer types:

Consultation Transfer (see 'Consultation Call Transfer' on page 313)

Blind Transfer (see 'Blind Call Transfer' on page 314)
Note:
18.5.2.2.1 Consultation Call Transfer
The device supports Consultation Call Transfer. The common method to perform a
consultation transfer is described in the following example, which assumes three call
parties:

Party A = transferring

Party B = transferred

Party C = transferred to
1. A Calls B.
2. B answers.
3. A presses the hook-flash button and places B on-hold (party B hears a hold tone).
4. A dials C.
5. After A completes dialing C, A can perform the transfer by on-hooking the A phone.
6. After the transfer is complete, B and C parties are engaged in a call.
The transfer can be initiated at any of the following stages of the call between A and
C:
•
Just after completing dialing C phone number - transfer from setup.
•
While hearing Ringback – transfer from alert.
•
While speaking to C - transfer from active.
Version 6.4
The device doesn't initiate call transfer, it only responds to call transfer
requests.
313
18. GW and IP to IP
November 2011