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Bridge the gap between analogue and digital

With Pre-digital Phone Line.

Deliver digital transformation in the best way for your customers and your business

Pre-digital Phone Line (PDPL) lets your customers keep legacy handsets and equipment while moving them off the public switched telephone network (PSTN).


This interim solution is ideal for edge use cases that rely on features of the analogue network, and it means vulnerable users won’t get left behind. 

Easy setup

Usually, no engineer visits or changes are needed on site.1

Great compatibility

PDPL works with the majority of legacy devices.


There’s minimal downtime for port and service conversion.

Ready to go

Works in places where broadband can’t support IP voice yet.

1. Site visits may be required in some situations, such as when dealing with hot sites.

What are edge use cases?

It’s not just telephones that use the PSTN. Many non-telephony devices rely on it too, including:

  • CCTV systems
  • Alarm lines
  • Lift lines
  • Cash machines
  • Emergency lines
  • Fax machines
  • Telemetry systems
  • Telecare devices
  • Payment terminals
  • Custodial tagging
  • Business continuity systems
  • Door entry systems

PDPL is designed to keep phones and edge case devices connected, while putting customers on the road to all-IP. It should work with most devices, but proper testing is crucial.


Please note: PDPL is for migrating single-line voice-only PSTN, not multi-line PSTN or PSTN with broadband. Featureline, ISDN2/30 are not compatible.

Protecting vulnerable users

As part of our commitment to connect for good, we’re signed up to the UK government’s Network Operator Charter.


This makes sure vulnerable people, including telecare users and those who depend on landlines, are protected throughout the transition to digital phone lines.


With PDPL, you can uphold the principles of the charter, so everyone can be included in the future of telecoms.

Additional info

The latest on PSTN

The deadline for the digital switchover is now 2027. Our IP Migration Director, Steve Blackshaw, explains what that means for you.

Testing your equipment

You can test devices at our Digital Services lab to see how they’ll work on our IP network and PDPL. You don’t even need to be a BT customer.

Frequently asked questions

Discover key information about Pre-digital Phone Line, including how to order it and how the migration process works.


Talk to us about your needs

Discuss your business needs with one of our experts, and discover how we can help you find success.