Pan-European ISDN services you can rely on

With over 20 years’ experience, and the most comprehensive Pan-European network, Colt is the ISDN provider of choice for thousands of businesses across Europe. Work with us to consolidate and simplify your voice services while reducing supplier costs. Shifting to Colt is easy. We minimise disruption to your business from set-up then guarantee to maintain service.


Cost-savings with reliability guaranteed

Cost Effective

One network and one supplier means one, reduced flat fee. You can also make extra cost-savings by moving to VoIP. Ask our experts how.


Our network is business-grade and robust. If the unexpected happens, your business will continue to run with our Disaster Recovery service.


With our Diamond Telecoms Expense Management tool you have complete visibility of call spend and traffic. This helps you see and manage costs better.

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Giuseppe Isola


Our objective is to be the best the market has to offer in every market in which we operate. Colt was able to appreciate the importance of this statement, and provided a service that offers the guarantees and the security our company needs.

It’s easy to change to Colt ISDN services


We have our own number pool across Europe as well as extensive porting capabilities. Keep your current numbers, or add new ranges, with no disruption to the business.


Control your telecoms spend with our competitive flat fee. We offer All Inclusive, Pre-Pay, and Pay-As-You-Go tariffs to suit customers of all sizes and traffic levels.  


Because we fully own and operate our own network across 50 geographically diverse, carrier grade switches we can guarantee you a seamless experience across Europe.

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How To Contact Us

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+44 (0) 20 7863 5510