Telephony replacement: analogue and critical lines

Addressing BT's removal of analogue telephone lines

BT is switching off analogue between January 2026 and January 2027.  To avoid the risk of service loss, all critical and analogue lines should be migrated from the existing Chorus telephony service to an alternative solution by the end of 2025 (if possible). 

What are critical and analogue lines?

  • critical lines are telephone lines that serve critical services, such as lift phones, alarm lines, and backup lines for college lodges. They can be used for inbound and outbound phone calls and will continue to work in the event of power outages or disruption to the Chorus phone system.  They use dedicated copper wiring and network infrastructure, and have a Service Level Agreement (SLA) which means that outages should be responded to by our suppliers within 4 hours 
  • analogue lines are like critical lines and use the same network infrastructure. The difference is that they usually provide telephony to a legacy device which cannot be digital, and that service is not critical to business operations

What does this mean for my college or department?

The table below outlines the options available for replacement of analogue telephony lines.  If you need further guidance on these or about how to mitigate for different service outages, please contact the project team.

Microsoft Teams Phone

Teams Phone (formerly 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.

 

Considerations for telephony in safety-critical locations

The following advice has been provided by the Safety Office:

  • there is no regulatory requirement to have physical emergency phones in laboratories, including higher risk spaces
  • the decision should be risk based, so considered on a case-by-case basis
  • lone working arrangements and the need or ability to summon assistance in an emergency should be taken into consideration
  • the decision, and therefore the risks, depends on the ability of someone in a higher risk space (e.g. a workshop, containment level 3 (biological) laboratory, or where working with radiation) needing and being able to obtain appropriate help quickly
  • connected phones should be available in laboratories, as reliance on mobile phones is not a suitable solution because of the risk of loss of signal and possible contamination of the individual's phone
  • the need for a physical phone can be considered quite low and unnecessary for most spaces
     

Existing line

Solution

 Responsibility for implementation
Analogue lift line

Via one of these options:  

  1. moving to GSM through  the Estates maintenance and modernisation contract  
  2. by individual colleges moving to GSM  
  1. Estates Services is coordinating the conversion of analogue lines in lifts that it manages. This is a separate programme of work, and they will be in touch with the appropriate person regarding timings
  2. Units with lift lines that are not managed by Estates Services should contact their lift maintenance company to arrange this work
Analogue line (non-lift) that can move to Teams Phone without a handset   Move to Call Queue in Teams Phone Telephony Coordinator by completing the Call Queues and Autoattendants’ Service Request
Analogue line (non-lift) in safety-critical location that can move to Teams Phone and requires handset  Poly handsets on Teams Phone Telephony Coordinator via Phoneman. Project will supply Poly Edge E100 handset (but not future handset purchases or replacements)
Analogue line (non-lift) that cannot be moved to handset e.g. alarm lines, electric meter lines, fax lines   Analogue Telephone Adaptor (ATA) to enable move to Teams Phone Telephony Coordinator via their alarm line/meter line provider.  A fax could work on an ATA, but this would not be a centrally supported service 
Other analogue lines that cannot be moved to Teams Phone Upgrade analogue line associated equipment that is incompatible with new technology (e.g. an ageing alarm system)    Telephony Coordinator but they should seek advice from the project  team first: contact telephonyreplacement@it.ox.ac.uk 

 

Critical and analogue lines not provided via Chorus

  • You will also need to review any analogue services that are not provided via Chorus.  This includes directly provided lines, which will not be covered by the Telephony Replacement project but will also need to be removed or replaced
  • Check your bill for details

 Detailed information 

Expand All

Date Activity
April - July 2025 Proposal of alternative solution(s), transition process and schedule, cost model, support model and pricing information and briefing of appropriate bodies (for example, committees)
April - November 2025 Ascertain college and department numbers of analogue and critical lines moving to Teams Phone
June - December 2025  Transition to Teams Phone (if possible) or suitable alternative
August 2026 Post-transition charging model comes into effect for Teams Phone

 

Please see the Telephony replacement distribution of costs webpage.

 

Details of the charging model for Teams Phone are available at Teams Phone Billing | IT Help.   The service will be supported by the Communication and Collaboration Services Team in IT Services. Service Requests will be updated to reflect this over the coming months 

  • Collection of Chorus handsets from individuals and common areas will be the responsibility of each individual college or department.  Where a college or department already has a Stone collection booked, it will be most efficient to use this for disposal of its handsets.  Otherwise, the project will coordinate removal of handsets from a single location for each college/department and their secure and safe disposal
  • The project will not fund the purchase of headsets or Teams Phone compatible handsets for individual users.  The project will fund Poly Edge E100 handsets or ATAs for those lines that move from analogue to Teams Phone, but will not fund not future or replacement purchases

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

See further information about supported devices on the IT Help website.

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