Extensions

What Are Extensions?

Extensions are internal dialing numbers that allow users to reach each other within the organization without using a full DID number. Before an extension can be assigned to a user, it must first exist in an Extension Pool.

Two Main Areas

Tab	Purpose
Extension Pools	Create and manage the inventory of available extension numbers
Assignments	Search and review how extensions are currently assigned to users

The Pool-First Model

Create Extension Pool
        ↓
Assign Pool to a Division
        ↓
Extensions become available for assignment
        ↓
Assign extension to user via Contact Information

⚠️ You cannot assign an extension to a user until it exists in an Extension Pool.

Task	Path
Open Extensions	`Admin → Telephony → Extensions`
Open Extension Pools	Extensions → Extension Pools tab
Open Assignments	Extensions → Assignments tab
Add extension(s)	Extension Pools → Add
Assign to user	`Admin → People and Permissions → People → [User] → Contact Information`

Required permissions:

Telephony > Plugin > All

Telephony > Extensions > Add, Edit, View, and Delete

Step 1: Create an Extension Pool

Step	Action
Step 1	Navigate to `Admin → Telephony → Extensions`
Step 2	Open the Extension Pools tab
Step 3	Click Add
Step 4	Enter Extension Start (single number, or first in a range)
Step 5	Enter Extension End — leave blank for a single extension, or fill for a range
Step 6	Select the Division
Step 7	Click Create

Extension Pool Fields

Field	Description
Extension Start	Single extension number, or first number in a range
Extension End	Last number in a range; leave blank for a single extension
Division	Access-control boundary for this pool

Step 2: Assign Extension to a User

Extensions are assigned through the user's profile, not from the Extensions page directly.

Step	Action
Step 1	Navigate to `Admin → People and Permissions → People`
Step 2	Search for the user and open Edit Person
Step 3	Open the Person Details tab
Step 4	Click View Edit Mode
Step 5	In Contact Information, click Edit
Step 6	Under Phone, enter the extension in the ext. field of an empty Work Phone entry
Step 7	Click Save
Step 8	Return to Extensions → Assignments to confirm the extension appears

⚠️ Critical: Enter the extension only in a Work Phone entry that does not already have a phone number. Adding an extension to an entry that already contains a number prevents Genesys Cloud from generating a dial plan for the user, and the extension will not appear in the Assignments page.

Key Rules

Rule	Detail
Pool first	Extension must exist in a pool before it can be assigned
Unique extensions	Duplicate extension numbers are not allowed
Empty Work Phone entry	Extension must be entered in an empty Work Phone slot, not alongside an existing number
DID and extension are separate	If a user has both, they must be separate phone entries
Range deletion	If an extension was added as part of a range, the entire range may need to be deleted — you cannot delete a single number from within a range
Assigned range deletion	Cannot delete an extension pool while any extension in its range is assigned to a user
Propagation delay	After assigning an extension, it can take up to 60 minutes before it is accessible in a Dial By Extension action

Assignments View

The Assignments tab lets you:

Search by extension number

View which user each extension is assigned to

Open the user's profile directly from search results

Customize visible columns and row density

Troubleshooting

Issue	Cause	Resolution
Extension not assignable	Not added to an Extension Pool	Add it to Extension Pools first
Duplicate extension error	Same number already exists	Use a unique extension
Extension not visible in Assignments	Entered in a Work Phone entry that already had a number	Remove and re-enter in an empty Work Phone entry
Cannot delete extension	Belongs to a range or is currently assigned	Remove the user assignment first, or delete the entire range
User not receiving calls by extension	Profile or dial-plan issue	Verify pool membership, user profile entry, and permissions
Dial By Extension not working immediately	Propagation delay	Wait up to 60 minutes and retest

Quick Reference

Question	Answer
Where do you manage extensions?	`Admin → Telephony → Extensions`
What are the two main areas?	Extension Pools and Assignments
What must happen before assigning an extension?	It must be added to an Extension Pool
Can duplicate extensions exist?	No
Where is the extension assigned to a user?	In the user's Contact Information, in the ext. field
Can you delete one number from a range?	Not if it was originally entered as part of a range
How long can Dial By Extension take to recognize a new extension?	Up to 60 minutes

Naming Convention

Resource	Example
Extension Pool	`Support_Ext_Pool_4100_4199`
Extension Pool	`Sales_Ext_Pool_4200_4299`

Pattern: <Division>_Ext_Pool_<Start>_<End>