ISDN Voice Services
ISDN Service Provider
Consolidate and simplify your voice services while reducing costs. A single network and supplier means one, reduced, flat fee, with extra savings to be made by centralising the telephony network through consolidation of Local Area Codes.
Using the ISDN Service in combination with Colt Business Internet Access can further decrease your costs and once you are fully IP ready, you can easily migrate to a SIP Trunking Service, which is even more cost effective.
Pan-European reach with reliability guaranteed
Our robust network is protected by Dual Homing, Disaster Recovery or Inbound Call Re-routing services, ensuring your business stays up and running should the unexpected happen. Because we fully own and operate our own network across 50 geographically diverse, carrier grade switches and SIP Trunking POPs, we can guarantee a seamless experience across 13 countries in Europe, compliant with all legal and regulatory requirements.
Flexible and transparent
Online call detail records (CDR) give you complete visibility of call spend and traffic, while All Inclusive or Bundled Minutes with Flat Fees or Pay-As-You-Go tariffs suit customers of all sizes and traffic levels.
Our own number pool across Europe as well as extensive porting capabilities allows you to keep your current numbers, or add new ranges, with no disruption to the business.
Future proof
Next Generation IP Technology can help customers transition from legacy telephony to new voice technologies, such as SIP Trunking and Unified Communications, enabling them to stay competitive and agile. 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.
Learn more
Want to learn more about our business phone services?
Check out the rest of the products below.
SIP Trunking Services
With SIP Trunking you simplify all your telecommunications into a single IP network. You keep all the features of traditional telephony, and call quality, while gaining a monthly cost saving as high as 50%.
Live chat with Sales
For all your purchase enquiries.
Monday to Friday 9am - 5pm
Contact us about ISDN Voice Services
ISDN Service Provider:
Call a specialist
Salesland
Salesland banks on Colt for its switch to VoIP. Salesland focuses on supporting businesses that want to outsource their sales services.
Contact Centre Solutions
Colt IVR services and virtual call centres, you can move to a state-of-the-art contact centre quickly — at a price you can afford.
Businesses finding their voice to empower customers
Businesses are seemingly finding their voices once again, with research showing that voice is likely to become the principal medium for dealing with the most complicated and potentially most business-critical customer interactions. …
Meet Ali, Technical Coordinator
“The best aspect of my job is that it gives me a full understanding of the network and processes around it, from order entry to billing. Colt has offered me a platform to learn and gain practical experience about innovative technology, but also offered me the opportunity to deliver for customers who rely on us.”
Careers at Colt
As VoIP gains more acceptance and demand increases, we’re confident that Colt is well equipped to accommodate our growth and will continue to provide us with the excellent support we always receive.Intercall
VP Telecoms EMEA, Intercall