# External Hot Desk User Callback

## Overview

External Hot Desk User (EHDU) Callback helps to eliminate or reduce outgoing call charges for EHDU users. When the system receives an authenticated call from the EHDU, it returns busy tone, and then disconnects the call. On hearing the tone, the user hangs up and awaits the callback. Using the calling party number received in the initial call, the system calls the user back, usually within a few seconds. After answering the callback, the user is presented with dial tone, and then dials the required number. This process can be expedited if the user's device supports "smart dialing."

This feature greatly reduces charges to EHDUs in different local calling areas than their home MiVoice Business system or on a mobile calling plans that charge for outgoing calls. In both cases, the user avoids charges for calls to the system since they can't be completed due to busy condition.

## Conditions and Feature Interactions

- EHDU authentication is provided by the Call Recognition Service (CRS). The service is triggered when the system receives the Hot Desking Access Number, regardless whether the calling trunk is configured to use CRS.

- Callback is only available on trunks that deliver calling party number.

- The EHDU must be logged in externally to receive Callbacks.

- Callbacks support Answer Confirmation, a Class of Service option that allows EHDUs to answer calls by pressing a DTMF key.

- Unanswered callbacks ring for the duration of the ringing timer in the EHDU Class of Service.

- If user fails to answer the callback, no retries are attempted.

- Callbacks will follow ARS alternate routing to the EHDU but not forwarding or rerouting in effect at the EHDU device.

- After a Callback is answered, the EHDU is routed to its home node for processing of any feature requests.

## Programming

- System Access Points form

- Enter the Hot Desking - Callback numbers

There are two numbers to enter. Each corresponds to the terminating digits of the DID number that EHDUs dial to request a Callback. One of the numbers allows users of smart phone devices, such as the RIM Blackberry® , to make the call using the device's smart dialing feature.

## Availability

This feature is available to External Hot Desk Users only.

## Operation

### Standard Device

To request a Callback from a standard EHDU device (the device must be logged in first):

1. Dial the DID number terminating on the required Hot Desking - Callback before digit collection number.

2. On hearing busy tone, hang up and wait for the callback.

3. Answer the callback.

4. Listen for dial tone, then dial the required number.

### Smart Dialing Device

Before using this feature, program the device with the Hot Desking - Callback before digit collection number (as the "smart dialing" number) and add the prefix “X” to your contact extension numbers (e.g. x1234).

To request a Callback from an EHDU device programmed with a smart dialing number (the device must be logged in first):

1. Select and call the contact’s extension number.

2. Wait for the system to disconnect the call, then hang up and wait for the callback.

3. Answer the callback.
   The system dials the contact’s extension.

Related Topics

- External Hot Desking - Description

- External Hot Desking - Conditions

- External Hot Desking - Programming

- External Hot Desking - Operation