What's inside the eBook
The eBook has nine chapters, from what PSTN and ISDN are to a six step migration plan. It takes about 15 minutes to read.
1
What PSTN and ISDN are, and why Openreach is closing the copper network.
2
The seven types of equipment that can stop working, and who to call about each one.
3
What Openreach's temporary EVAc service covers, and what happens in a power cut.
4
How business broadband, cloud phone systems and SIP trunks fit together.
5
Six steps to move your business with little or no downtime.
6
A one page form to print and take round your building.
7
How Bredon Hill Academy cut its telecoms costs by more than 30%.
8
Straight answers on numbers, alarms, card machines and cost.
9
What to do this month, and who to talk to.
Preview: the line and device audit
Page 9 is the one to print. Take it round your building with your phone bill and tick off each line as you find it. Alarm diallers and lift phones are the ones people forget, so they are on the list. Here are the first five rows.
| Line or device | Why it matters | Where to find it |
|---|---|---|
| Analogue phone lines | Stop working when the copper line is removed | Line rental on your phone bill |
| ISDN2 / ISDN30 | Withdrawn on the same timeline as analogue lines | Your bill, or your phone system maintainer |
| Alarm dialler | May stop reporting to the monitoring centre | Alarm panel or monitoring contract |
| Lift emergency phone | A safety obligation that must keep working | Lift maintenance contract |
| Card payment terminal | Terminals that dial over a phone line stop taking payments | Merchant services agreement |
The full printable version has 12 rows with space for an owner and a date.
See the Phone System Integration in Action
You need to know the risk, the deadline and what it will cost to fix. Chapters 2 and 5 cover that.
You probably know where the bills, the alarm panel and the card machine are. The audit on page 9 is written for you.
You get a device by device list to plan the move across one site or several.
Lift phones, door entry and alarm lines sit in your contracts. Chapter 2 shows who to contact about each one.
Three dates every business should know
Openreach stopped selling new analogue phone lines across the UK.
BT announced it was moving the final deadline from December 2025 to January 2027.
What to do this month, and who to talk to.
For the full timeline and what each stage means, read
The Big Switch Off 2027: UK business guide.
Prefer to read online?
Every topic in the eBook has a full article on our site.
Frequently Asked Questions
Is there a free BT switch off guide for businesses?
What does the BT switch off guide cover?
What format is the eBook?
Who is the eBook written for?
How up to date is the eBook?
Can I share the eBook with my team?
Watch: is your business ready?
A short video from our team on moving a business from analogue lines to a cloud phone system.
Get the guide, then plan your move
Download the eBook and work through the audit. When you know what you have, our UK team will plan a switch date that suits your business and keep your existing numbers.