9.15.4 Call Transfer
There are two types of call transfers:
Consultation Transfer (REFER and REPLACES):
The common way to perform a consultation transfer is as follows:
In the transfer scenario there are three 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.
Blind Transfer (REFER):
Blind transfer is performed after we have a call between A and B, and party A decides
to immediately transfer the call to C without speaking with C. The result of the transfer
is a call between B and C (just like consultation transfer only skipping the consultation
stage).
Notes:
SIP User's Manual
•
Transfer is initiated by sending REFER with REPLACES.
•
The device can receive and act upon receiving REFER with or without
REPLACES.
•
The device can receive and act upon receiving INVITE with REPLACES,
in which case the old call is replaced by the new one.
•
The INVITE with REPLACES can be used to implement Directed Call
Pickup.
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MP-11x & MP-124
Document #: LTRT-65412