Telephony replacement: analogue and critical lines

Addressing BT's removal of analogue telephone lines

The current telephony contract will end in July 2026, meaning the University will need to migrate all critical and analogue lines from the existing Chorus telephony service to an alternative solution by that deadline. 

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 places that 'VOIP' (Voice Over Internet Protocol) telephony couldn't easily reach at the time of installation, and that the service is not critical to life or business operations

What does this mean for my college or department?

Colleges and departments have provided information about critical and analogue telephony requirements for lifts and alarms to the project team.

Most departmental lifts are maintained by Estates. If this does not apply to your department and you manage your own lift line, please notify the project team as soon as possible.

If you are aware of any other analogue lines purchased directly from BT that have not yet been flagged to the project team, and you require guidance, please contact the team via the project mailbox.

All colleges must arrange to migrate their remaining analogue and critical lines to digital (GSM) by July 2026. Most departmental lift and alarm line changes will be managed by Estates. However, departments not covered by Estates’ maintenance contract should make their own arrangements to transition to GSM by the same deadline.

The Telephony Project will not cover costs for GSM transitions but will pay for remaining analogue and critical line charges for 2025/26. Colleges and departments should continue liaising with the Chorus team to confirm which lines can be ceased, whether additional lines are required, which lines are critical and which are analogue, and whether any lines have already moved to another service.

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
  • We hold some records for directly provided BT lines and will provide support and advice where possible 

 Detailed information 

Expand All

Date Activity
April - July 2025 Proposal of alternative solution(s), migration 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 Telephony over Teams
April - November 2025 Post migration charging model shared for consultation
April 2025 - July 2026 Migration to new solution(s), if not Telephony over Teams
September 2025 - July 2026 Migration to Telephony over Teams
August 2026 Post-migration charging model comes into effect

 

  • Departments and colleges will need to cover the cost of converting lines to GSM solutions before July 2026 for lines managed centrally
  • Departments and colleges might need to budget for costs to upgrade associated equipment (e.g. an ageing alarm system that may be incompatible with new technology) or for analogue lines they manage themselves
  • To offset these costs, the project will cover the costs within the charging model for the remaining centrally managed analogue and critical lines during 2025/26 until the Chorus service ends in July 2026
  • A charging model for operating the analogue lines after migration will be considered, starting from August 2026. Information about the new charging model will be shared in Michaelmas term 2025

 

Information about the new service model will be shared when available.

Can colleges or departments with analogue lines managed by IT Services decide not to take the centrally recommended solution?

Yes, but only by moving to manage the lines themselves and also moving to new numbers. IT Services numbers cannot be ported to other suppliers.  All analogue lines will need to be replaced before July 2026.

Can colleges or departments who manage their own analogue lines now transfer these now to be managed centrally by IT Services?

No, IT Services will not be able to support analogue and critical lines once they are moved to GSM. A support agreement will need to be established with your current lift or alarm maintainer. In the future, departments may be able to take advantage of maintenance agreements arranged by Estates.

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