Consultation Call Transfer

The device supports Consultation Call Transfer.

The common method to perform consultation transfer is described in the following example, which assumes three call parties:

A = transferring party
B = transferred party
C = transferred to party
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 on-hooks the phone to transfer the call so that the call is established between B and C.

The transfer can be initiated at any of the following stages of the call between A and C:

Immediately after A completes dialing C (transfer at call setup)
While A hears a ringback (transfer from alert)
While A speaks to C (transfer from active)

The Explicit Call Transfer (ECT, according to ETS-300-367, 368, 369) supplementary service is supported for PRI trunks. This service provides the served user who has two calls to ask the network to connect these two calls together and release its connection to both parties. The two calls can be incoming or outgoing calls. This service is similar to NI-2 Two B-Channel Transfer (TBCT) Supplementary Service. The main difference is that in ECT one of the calls must be in HELD state. The ECT standard defines two methods - Implicit and Explicit. In implicit method, the two calls must be on the same trunk. PRI uses the explicit mechanism.