The direct replacement for ISDN ahead of the UK switch-off on 31 January 2027, designed for reliability and flexibility, and set up by you in the Plustel portal.
The direct replacement, side by side with what it replaces. IP connectivity costs less, with lower monthly rental and generally lower call charges.
| ISDN | Plustel SIP trunk | |
|---|---|---|
| Monthly rental | Higher | Lower |
| Call costs | Standard | Generally lower |
| Moving office | Call forwarding costs | Keep your number |
| Multiple sites | A PBX at every site | Fewer PBXs to maintain |
| Voice and data | Separate services | One Ethernet connection |
| Adding capacity | Order new circuits | Add channels in the portal |
| Future | Switched off 31 Jan 2027 | The direct replacement |
Every connection comes fully loaded with value-added features as standard.
High quality voice and data over one Ethernet connection, giving significant cost savings.
Calls generally cost less than on ISDN.
Built into the service, ready when needed.
Bring existing numbers across to the trunk.
Value-added features at no extra effort.
A phone service that copes with any situation, so the business keeps running without expensive call forwarding during difficult circumstances.
If the office has to move in an emergency, calls follow quickly and cost effectively.
Calls re-route if a line or site goes down, so customers still get through.
Move premises and keep the same geographic number, with no ongoing forwarding costs.
Plustel SIP connections are built for resilience from the first call.
SIP trunking gives businesses with several sites ISDN line rationalisation options and reduces the number of phone systems to maintain, with every business number kept under your control.
The national PSTN and ISDN switch-off is confirmed. Every customer still on ISDN needs to move, and SIP trunking is the direct replacement.
Audit ISDN lines and the PBXs they serve.
Bring numbers across and add trunks in the portal.
The national PSTN and ISDN networks close.
Provision connections yourself, any time of day, then search for and locate any SIP connection on your account.
Choose the number the new trunk will present.
Specify how many simultaneous calls are needed.
Select the type and the connection is created.
New to SIP trunking? Read What is SIP trunking?, compare hosted PBX vs SIP trunks, see business SIP trunks, or find out what the ISDN switch-off means.
Plustel SIP trunks are affiliated with eight leading PBX vendors, so the phone system your customer already owns can stay.
SIP trunking enables voice communication between a telephone system (PBX) and the telephone network. It is the direct replacement for ISDN circuits ahead of the UK's national PSTN and ISDN switch-off, confirmed for 31 January 2027.
Yes. A SIP connection allows you to move office and keep the same geographic number, without any ongoing call forwarding costs.
IP connectivity costs less than ISDN, with lower monthly rental charges and generally lower call costs as well.
Plustel SIP connections are designed to give 99.9% uptime on your telephony, so your business keeps running without expensive call forwarding costs during difficult circumstances.
New SIP trunk connections can be added within the Plustel portal by selecting a SIP CLI, specifying the number of channels required, and then selecting a SIP trunk type. You can search for and locate any SIP connection associated with your account.
Yes. For businesses with multiple sites, SIP trunking provides ISDN line rationalisation options and reduces the number of PBXs you need to maintain, with full control of your business numbers.
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