ISDN vs Sip Trunking

As technology improves, companies that focus on structuring their vision for the future will adopt and utilise new productivity tools and integrated networks. This is for the purpose of remaining competitive, but also to remain confident and capable in serving clients and supporting staff alike.

Voice calls have been a common necessity for businesses, phone networks and VoIP serving as the most essential implementations of any business. In 1986, BT introduced Integrated Service Digital Networks (ISDN), it replaced analogue lines, moving to digital added features that weren’t previously available.

While this ISDN has been useful for quite some time, BT announced back in 2015 that they will shut off the ISDN network in December 2025, it’s now time for an update. SIP trunking (SIP = Session Initiation Protocol) is one option to consider when moving off ISDN, if your current phone system enables the use of SIP then this cost-effective solution allows you to future-proof your telecommunications whilst retaining your existing phone system.

But what does SIP trunking have over ISDN? In this post, we’ll compare and contrast both protocols so you can make more informed decisions regarding the network integrity of your firm as we move into the future.


The Differences Between ISDN & SIP

ISDN is a proven technology, introduced in the 1980s it has been a reliable solution, provided over copper wires it has given businesses the flexibility to manage multiple calls and have multiple numbers (DDI). Since ISDN was introduced, technology has evolved dramatically and the current ISDN network is no longer fit for purpose. Internet Protocol (IP) is now the technology of choice, in 2015 the number of IP circuits ordered surged ahead of ISDN connections and has remained at the forefront of ever since.

SIP trunks are a type of technology that allow you to make calls over an internet connection.  It’s a direct replacement for ISDN rather than converting to a new system. If you wish to keep on-premise phone hardware and have complete ownership of your telephony system, then SIP trunking is the best option for you. To use SIP your business will need a PBX that supports IP traffic (IP PBX) or a SIP trunk Gateway.


How should I prepare for SIP trunking integrations?

BT has announced that the ISDN switch-off is to come in 2025. As such, now is a great time to start thinking about your transition. Don’t worry though, the process will save you money and maintenance efforts over the long haul, so this is a rare win-win.

Pescado serves as the all-service business IT and telecom solution, providing consultations and ultimately outfitting your business to take your communications to the next level.

Feel free to contact us at any time, or browse our business connectivity pages for more information.