• PBX Hot Desking
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PBX Hot Desking

This article describes how to set up and configure the Infinity PBX Hot Desking feature, enabling multiple users to log in and make calls on a single PBX enabled handset.

Introduction to Hot Desking

The Infinity PBX Hot Desking feature enables multiple users to log in and make calls on a single PBX enabled handset using their four-digit operator extension number and PIN. This means an operator can be the temporary physical occupant of a handset, and therefore work station, ultimately reducing cost where not all employees are in the office at the same time.

This is also a great feature if you need to make PBX Voicemail changes on behalf of your PBX users, but cannot physically access their phones to do this - for example, because they are based in remote offices.

Compatible Handsets

Most modern SIP enabled handsets will be compatible with hot desking, as many handsets from popular brands are equipped with hot desking features that cater for registering to our PBX network out of the box.

However, make sure your handset’s hot desking feature allows registering with both a username (the operator’s extension number) and a password (the operator’s preferred PIN). Some handsets only cater for the former and will be rejected by our network for sending no password at all.

As with the rest of our PBX system, we recommend using Yealink brand handsets. Infinity’s Hot Desking feature is tested to work seamlessly with the T4x series and higher, although older T38 handsets are also compatible.

Handset Setup

Any handsets intended for use with hot desking will need to be configured to show an option for its hot desking feature, which will in turn allow the operator to register with their operator extension and PIN.

On Yealink T4x and T38 handsets, this can be done by adding a DSS Line Key. How you achieve this will depend on how your handsets are provisioned. Unfortunately, we are unable to offer support or guidance on non-Yealink handsets.

Provisioning Server

If your PBX handsets are set to automatically provision their configuration from a provisioning server, you’ll need to add a DSS Line Key setting to the .cfg file. For a Yealink handset, this will appear as follows:

linekey.3.line = 0
linekey.3.value = 
linekey.3.pickup_value = 
linekey.3.type = 34
linekey.3.xml_phonebook = 
linekey.3.label = Hot Desking

Any parameters that are blank do not require values for Hot Desking. On most Yealink handsets, the Hot Desking feature is type 34.

The integer in ‘linekey.3’ represents the position/ID of the line key you wish to use for the Hot Desking option on the handset. Your Yealink user manual will specify the range of IDs catered for by your handset.

It’s also advisable to remove the requirement for the operator to enter a server when registering to Hot Desking. Without doing this, the operator will be asked for both their username and password, but also to enter the server they wish to connect to; this increases the likelihood of human error leading to failed registrations. Instead, we recommend adding the following configuration line to your .cfg file:

hotdesking.dsskey_sip_server_enable = 0

By adding the above line, the handset will default to using the first SIP account on your handset when hot desking, negating the requirement for the operator to enter it manually.

When these settings have been saved in the .cfg file and the handset next comes to auto provision, the Hot Desking feature will be offered to your operators on the line key you specified.

Individual Handsets

If you’re already set up to individually configure your Yealink handset from the web interface of each device, you’ll need to head over to the handset’s IP and log in.


  • To set up a new line key, navigate to the DSS Keys area, and then select the Line Keys tab.


  • Under the line key you wish to change, select the Type drop down and select the Hot Desking value. The Value field is not required, so don’t add anything in there.

  • Leaving the Label field blank will default the title of the line key to the feature’s name. In this case, leaving it blank will result in the line key being labelled “Hot Desking”. If this isn’t what you’d like to show to your operators, just enter a different value in this field, such as “Register”.

  • Both the Line and Extension fields should be disabled, as they aren’t compatible with Hot Desking, if the fields aren’t disabled on your web user interface, simply leave them blank.

  • Finally, click Confirm to save your changes.

  • Your operator’s handset will now refresh and offer the Hot Desking feature on the line key you previously chose.

SIP Expiry Time

It is also important to ensure that your handset is set to re-register at least every ten minutes. Set it to 500 seconds This prevents the operator from timing out and ensures calls will also be routed to their hot desked location.

On Yealink T38 handsets, this setting can be found in the web user interface under Account > Advanced named Login Expire (seconds). On T4x handsets, this option can be found under the Account main page, directly below the SIP server settings, labelled Server Expires.

Trusted IPs

Now that your operators have access to registering on a handset with the Hot Desking feature, you’ll need to whitelist their location’s IP address (or multiple) in order for the handset to connect to the network. Without doing this, your location will not be permitted to connect to the network when using Hot Desking to prevent registrations by operators from locations you don’t specifically authorise.

  • To view and manage your trusted IPs, log in to your Infinity PBX installation, and navigate to Telephony Settings.


  • Select the Phone System Install you’d like to edit.


  • Then, select the Trusted IPs tab. Within the Trusted IPs section, you’ll see a list of IP addresses or ranges that you’ve previously chosen to whitelist. If you’re new to Hot Desking and you’re setting it up for the first time, this list will be blank and no locations will have access to Hot Desking yet.


  • To add a new address or range, simply enter the value into the IP range field at the bottom of the list, and press Add IP Range. Don’t forget to add a description for future reference so that you know which location this is authorising access from.

Values within this list need to be in the ipv4 format; ipv6 is not yet supported. Only ipv4 ranges are permitted, and values must be a CIDR address in the format

If you’re unsure of this value, please contact your IT administrator for more information on the IP range you need to enter.

User Setup

If you’ve followed this article step by step to this point, your handsets are now set up to provide the Hot Desking feature and your call centres, offices or other locations are authorised to connect.

However, if your operators try to register to the network with their extension and PIN, they first need to be allowed to use the feature. This is a simple amendment to their user settings within the Infinity portal.

Allowing Access

  • To grant a PBX user with Hot Desking permissions, log in to your Infinity PBX installation, and navigate to Telephony Settings.


  • Select the Phone System Install you’d like to edit.

  • Select the Users tab.


  • Click the Edit option next to the user you’d like to grant permission to.


  • Within the User Settings page, tick the Hot Desk Access checkbox and then Save.

Creating a Hot Desking PIN

When an operator elects to Hot Desk and temporarily register on a handset, they’ll need to enter a PIN to authenticates themselves. This PIN is a four-digit code that’s defined, per user, on the Infinity Portal.

  • Log in to your Infinity PBX installation, and navigate to Telephony Settings.


  • Select the Phone System Install you’d like to edit.

  • Select the Users tab.


  • Click the Edit option next to the user whose PIN you’d like to alter.


  • Within the Hot Desk Pin field, enter the four-digit PIN you’d like to set for the user.

  • Click Save.

Using Hot Desking

Logging In

When Hot Desking has been set up on your phone as a line key, simply select the line key option. The label for this option depends upon what’s been set up in previous steps of this article. If you didn’t set it up, ask your system administrator which option you should use for your handset’s Hot Desking feature.

After selecting the Hot Desking option, a dialogue window will appear asking you to “clear all account config” on your handset. This simply prevents more than one user logging in at the same time. Select OK. You’ll then see two or three options:

  1. Username – Enter your operator extension number. This can be found within the Infinity PBX portal, under the Real Time Dashboard report.
  2. Password – This is the four-digit PIN for Hot Desking. If you’ve forgotten your PIN, please contact your administrator to request a new one.
  3. Server – If this field has not been hidden from your user interface, you’ll need to manually enter your PBX server. Please ask your system administrator what this value should be, as it’s different for every Infinity customer.

When you’ve entered these values, just press Save to register on the network and begin Hot Desking.

Making Calls

When Hot Desking, you can continue to make calls as you would normally on any handset. All calls will be mapped back to your operator on call logs and dashboards.

Logging Out

To log out Hot Desking, press the Hot Desking option on the handset. Just like logging in, you’ll be asked to clear the account config for the handset. Simply press **OK **– this will de-register you from the network.

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