R0106-HP MSR Router Series Voice Configuration Guide(V7)

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C (the final recipient). After Subscriber A hangs up, the call between subscriber B and subscriber C is
established. This is call transfer.
There are three types of call transfer:
• Unattended transfer—The originator hangs up before receiving ringback tones from the final
recipient.
• Half-attended transfer—The originator hangs up after receiving ringback tones from the final
recipient and before speaking with the final recipient.
• Attended transfer—The originator hangs up after speaking with the final recipient.
During the call transfer process, if the recipient does not support call transfer or the final recipient is busy
or provides no reply, the initiator can re-establish the original call.
Call backup
primary link might be unavailable when the calling party initiates a call through the IP or PSTN network.
In this case, if there is a backup link (PSTN link or VoIP link) to the called party, the calling party can
reinitiate a call to the called party over the backup link. This is call backup.
MWI
Message Waiting Indication (MWI) can notify a user that there are new messages in the voice mailbox
by playing an MWI tone when the user picks up the phone. This feature works with the voice mailbox
function of the voice mail server, allowing users to be informed of mailbox status without performing
query operations.
The process for MWI is as follows:
1. If a subscriber misses a call, the call is redirected to the voice mailbox.
2. The voice mail server sends a NOTIFY message to notify the SIP UA.
3. The SIP UA notifies the user that there is a change in mailbox status by playing an MWI tone when
the user picks up the phone.
Other indication methods such as LED are not supported.
Three-party conference
The process for initiating a three-party conference is as follows:
1. In an active two-party call, one party presses hookflash as the conference initiator and dials a third
party to establish a new call.
2. The conference initiator presses hookflash again and then presses 3 to start a three-party
conference.
The other two parties are called conference participants.
When the conference initiator hangs up, the three-party conference is released, and all calls are
disconnected. When a conference participant hangs up, the other two parties can continue their call.
As shown in Figure 46, a thr
ee-party conference is established among Telephone A, Telephone B, and
Telephone C. Telephone B is the conference initiator.
The conference initiator can switch between the three-party conference and multiparty call hold service
as follows: