Call Transfer (Zenitel Connect Pro)

Call transfer is a feature used during an established two‑party call. One party can transfer the active call from their own device to another device or service.

The following call transfer methods are supported:

Blind Transfer: Transfers the call immediately without consulting the receiving party.
Attended / Semi‑Attended Transfer: Allows the user to establish a consultation call with the target before completing the transfer.
Ad‑hoc Conference: Lets the user add a third party to the ongoing call, creating a temporary three‑way conference.

Terminology

Transferee: the party being transferred to the Transfer Target.
Transferor: the party initiating the transfer.
Transfer Target: the new party being introduced into a call with the Transferee.

Attended Call Transfer

The following procedure applies while you are in an active two‑party call.

1. Start the Consultation Call

Press digit 2. Initiates attended (consultation) transfer mode.
Dial the transfer target, then complete the entry with M or #.

2. While the Consultation Call Is Ringing

Abort the consultation call: Press digit 1
- (Returns you to the original call.)
Semi‑attended transfer: Hang up before the target answers
- (The system completes the transfer even if the target has not accepted.)
If the transfer times out or the target rejects the call, ZCP calls back the transferring party.

3. After the Consultation Call Is Answered

Swap between the two calls: Press digit 2
- (Repeat digit 2 to toggle back and forth.)
Abort the consultation / cancel transfer: Press digit 1
- (Returns you to the original call.)

4. Completing the Transfer

Transfer the call:
- Hang up, or
- Press digit 3

5. Create an Ad‑hoc Conference

Include all three participants: Press digit 4

Timeout for answer on attended transfer follows the Global Answer Timeout.

Blind Transfer

The following procedure applies while you are in an active two‑party call.

Dial 52
Dial the transfer target, then complete the entry with M-key or #.

ZCP does not call back to transferor if transfer times out.

Configuration

Apart from Call Service permissions, there are no specific configuration options for Call Transfer.

Call Service Permission

The permission for Call Transfer is not included by default in the “Default” Call Service profile. A dedicated Call Service permission, “Call transfer”, must be enabled.

Its related‑to range and feature‑type settings determine which devices or services a user is allowed to transfer calls to.

The following feature types are typically valid transfer targets:

Device numbers
Call queue numbers (e.g., return the call to a queue)
Trunk prefix numbers

For a call transfer to succeed, the call must match both:

The “call‑to” permissions
The “call transfer” permissions

You can safely grant Call Transfer permission to “all”, as the existing “call‑to” permissions still enforce the allowed destination ranges.

However, you may also choose to apply additional restrictions to limit call transfers to a specific subset of the permitted “call‑to” ranges.

Support for device built-in call transfer

In addition, Zenitel Connect Pro supports the device’s built‑in SIP REFER–based transfer, including both blind and attended transfers.

The exact functionality and user interface depend on the specific phone model.

Link API

The call looks like one three legged call during consultation call. The call leg state ”hold” shows which leg is inactive.

Device side call transfer
If user choose to use device built-in call transfer (based on SIP REFER) on a device that support it, the consultation call is reported on Link API as a second, regular call. On attended transfer (SIP REFER with Replaces), the Link call_id of the transfer target call leg is replaced with the call_id of the first call.

Additional notes

All call transfer calls, both blind and attended, go through the normal call setup process, including forwarding.
It is not possible to use a DAK-key to make transfer/consultation call. Only dialing through digits are supported.
When calling out on SIP trunk (External Communication), Call Transfer is not possible (because all DTMF digits need to be forwarded to other side). If the remote node is a Zenitel Connect Pro, call transfer is still handled, but in the remote ZCP.
There is no Link API available for initiating call transfer
It is not possible to grant permission for server side consultation call without also allowing call transfer.