ISDN is out, SIP is in | Digiquip

ISDN is out, SIP is in

SIP telephony is quickly overtaking ISDN so it is important to get acquainted with this next-generation technology. It won’t be long until telecoms operators stop offering ISDN and instead will be providing SIP trunking. Here are some interesting facts about the soon-to-be defunct ISDN and the new, flexible SIP trunk:


ISDN use is in decline


ISDN channels used by businesses in the UK have dropped off by almost 40% over the past 8 years.


(Sources: Ofcom The Communications Market 2013 /


In one year almost a third of a million ISDN channels were replaced.

 replaced lines


BT plans to completely switch off it’s ISDN network in 2025


Switch off


Why is ISDN in decline?

The main reason that ISDN is in decline is due to businesses requiring more flexibility from their telephone systems. SIP trunking can provide this flexibility by:


Retaining geographic numbers

Allowing organisations to move offices but still retain the same geographic numbers with no extra forwarding costs.

Preserving business continuity

Preserving business continuity by re-routing calls to alternative destinations in times of disruption, for example if you need to temporarily re-locate your office.

Reducing call costs

Reducing call costs due to the fact IP connectivity is cheaper than ISDN. Internal calls are also free and you will not receive any forwarding costs.

Providing line rationalisation

Providing line rationalisation which reduces the number of PBXs which can be hosted in the cloud.

Offering 100% uptime

Offering 100% uptime meaning your phone service can manage any emergencies.

Using a single connection

Using one connection for both data and voice services.


contact us

Contact us now for information and pricing on SIP trunking to bring your businesses phone system to the next generation!