Colt IN over Carrier VoIP – wholesale VoIP services specifically addresses the needs of Service Providers looking for dial-in numbers for their call centres and conferencing services in Europe.

Simplify your business

Manage all your inbound traffic to your Intelligent Network (IN) services across Europe with one single SIP interconnect.

We collect your IN calls and deliver them to your VoIP platform over our award-winning carrier-grade network in a scalable and cost-efficient way – fully compliant, supporting all country specific regulation.

Flexibility that meets your needs

Our comprehensive IN Services  (cloud telephone systems) portfolio offers you Freephone, Shared Cost, Premium Rate and geographic numbers in 13 European countries.

Choose the SIP interconnect option which fits your business requirements (Ethernet services, IP VPN with a guaranteed quality of service or public internet to connect your businesses worldwide).

Bill your end-customers in a flexible way with our twice daily standardised unrated CDRs.

Keep it simple and regulatory compliant

Stay focused on your business. Avoid complexity of contracting with multiple national operators and investing in local processes – with a unique, pan-European customer experience.

With more than 20 years’ regulatory experience, and our award-winning network, we are the European partner of choice for business phone numbers.

Learn more

Want to learn more about our service provider solutions for wholesale voice services?
Check out the rest of our products below.

White Label VoIP Services
With Colt, you can grow your business by offering more products, more rapidly, with only limited investment.

Number Hosting – VoIP Reseller Services
Build and sell your own VoIP services with Colt’s Number Hosting, use your own brand with this minimum effort and low risk solution.


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For all your purchase enquiries.
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Contact us about IN over Carrier VoIP:

Call a specialist

+44 (0) 20 7863 5510

Case Study


Salesland banks on Colt for its switch to VoIP. Salesland focuses on supporting businesses that want to outsource their sales services.

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“Colt has been an evolving company for quite some time, and working in sales has been a fulfilling role where you can see diversity in the company. It’s an environment where people can thrive and you can get a lot of enjoyment from the job”

Careers at Colt
Colt is a convenient one-stop shop for network and numbers in the 13 countries from which the majority of our European conferencing traffic comes. Amanda Thomas
VP Telecoms EMEA, InterCall