Telephony replacement: digital lines (VoIP telephony)

BT plans to switch off all analogue telephone services between January 2026 and January 2027 which means the University needs to migrate its critical and analogue lines from the current Chorus telephony service to a chosen alternative solution by the end of 2025.  

The Chorus service contract (provided by ATOS/Mitel) ends in July 2026 and the University is taking this opportunity to move to a new cloud-based supplier.

Leveraging the University's relationship with Microsoft, the preferred new service will be Microsoft Teams Phone (subject to approval by appropriate decision-making bodies).​There are approximately 3000 University or college staff already using Teams Phone.

 

Microsoft Teams Phone

Teams Phone (previously referred to as Telephony over Teams at the University) is part of the Microsoft Teams application and offers the user the ability to make and receive telephone calls through their Microsoft Teams client on any device. It also includes other functionality you would expect from a telephony service, for example the ability to transfer calls, receive or leave voicemail messages etc.

Note: Phone calls received via Teams Phone can be transferred to an individual through Teams even if the recipient does not have a Teams Phone line

What are digital lines?

Digital lines refer to VoIP (Voice Over Internet Protocol) telephony, as opposed to analogue lines that use dedicated copper wiring and network infrastructure.  If you have a Chorus desk phone, this uses VoIP telephony which is a digital line.

What does this mean for my college or department?

All existing Chorus desk phones will be removed and the project will not supply personal handsets or headsets.  

Personal users can use Teams Phone through:

  • their computer’s inbuilt microphone and speaker  
  • a headset (that they might already be using for Teams meetings)  
  • Teams Phone compatible handset (if paid for by their department or college)  
  • the Teams Phone app on their personal mobile phone or tablet  

The table below shows the Teams Phone equivalent for selected activities that might be in use in Chorus:

Chorus  Teams Phone
Hunt Group Call Queue
Pickup Group Call Group
EA Group Call Delegation

 

People in dual roles

People in dual roles may have a personal line and a ‘role-based’ line.  Only one telephone number can be associated with an SSO, so colleges or departments who want to provide a ‘role-based’ line will need to request a Common Area Phone for this purpose.  They will also need to pay for a Shared Area Device licence if they want to use a handset, and they will need to pay for the handset itself.  Alternatively, the ‘role-based’ line can be associated with a Call Queue, which when dialled could deliver the call to the user's ‘personal’ line.  This could remove the requirement for a handset, and the associated costs.  In this scenario voicemails for the personal line would be delivered to the user’s email address, and voicemails for the Call Queue would be left in the mailbox associated with the Queue.  We can set rules on this mailbox to deliver the voicemails to specified Oxford email addresses. 

Transitioning personal lines to Teams Phone

Telephone coordinators can already move personal lines to Teams Phone using Phoneman, and will be responsible for undertaking this at the appropriate time. 

There are more than 10,000 common area devices in use currently across the collegiate University.   These are handsets located in communal or shared areas allowing more than one person to make or receive calls (for example, receptions areas, porters’ lodges).  The introduction of Teams Phone could result in some of these common areas no longer requiring a physical handset and the table below outlines the options for moving these lines.  If you are unsure about the best solution to use or need further advice, please contact the project team.

Each common area phones (CAP) requires a Shared Area Device licence which is charged annually.

 

Current Chorus configuration Suggested alternative How to achieve this Associated cost  
Hunt group Teams Call Queue/Autoattendant Complete the ‘Call Queues and AutoAttendants’ Service Request  via the survey spreadsheet (supplied to Telephone Coordinators at appropriate time) None  
Common area phone, e.g. lodge/library/lab etc where a phone is required  Teams Desk phone using a Shared Area Device licence 

Basic handsets will be provided for up to 10% of common area lines by the project to be allocated to locations on a risk basis by the department or college  

Colleges and departments can order additional handsets, as required, for which they will have to pay 

Your network will require configuration, a device will need to be ordered/configured/deployed, and a Shared Area Device account created for you. Contact the project team

Up front hardware cost, future hardware refresh cost   
    
Ongoing Shared Area Device licence fee and line charge under new cost model   

 
Common area phone, eg lodge/library/lab etc where a phone is no longer required   Move the extension to a Teams Call Queue/Autoattendant. Provide Teams Phone to the users who need to answer these calls.  This will facilitate hybrid working
  1. Assign the users who will handle calls Teams in Phoneman  
  2. Complete the Call Queues and AutoAttendants Service Request
Ongoing annual line charge under new cost model  
Intercoms Reconfigure these devices to talk to a user on Teams   Contact the project team, which will handle these on a case-by-case basis To be determined individually  

 

Transitioning common area line to Teams Phone

Telephone coordinators will be able to move non-people lines to Teams common area lines when new functionality is available in Phoneman, which is likely to be in Michaelmas term. 

Detailed information

Expand All

Date Activity
June to April/May 2026  Ascertain college and department requirements for shared area digital lines and equipment
June to September 2025 Approval of proposed solution (Teams Phone), transition process and schedule, consultation on charging model, support model and pricing information 
From August 2025 Transtion to Teams Phone, facilitation of new equipment purchasing and management of new service

 

Further information about the service charging model will be shared when available. The service will be supported by the Communication and Collaboration Services Team in IT Services. IT Help webpages and Service Requests will be updated to reflect this over the coming months 

  • Collection of Chorus handsets from individuals and shared areas will be the responsibility of each individual college or department.  The project will coordinate and fund removal of handsets from college/department building(s) and their secure and safe disposal
  • The project will not fund the purchase of  headsets or Teams Phone compatible handsets for individual users. Basic handsets will be provided for up to 10% of common area lines by the project, to be allocated to locations on a risk basis by the department or college

NOTE: Teams Phone can be used without a handset or headset through the computer's inbuilt speaker and microphone.

See indicative costs for Teams Phone compatible handsets on the IT Help website.