CallMe: Transformation of IP Telephony

Leading Denmark's IP Telephony with Innovation and Expertise

As the chief developer and operations manager at Debitel, I led GoIP, one of Denmark's largest IP telephony providers. With over 100,000 private customers and many large business clients, GoIP was a flagship in the industry.

Overcoming Technical Challenges

When I took over the role, there was no handover from the original developers. I faced a complex and challenging task: to maintain and improve a solution based on Asterisk with a PHP platform for provisioning, CDR (Call Detail Record), and billing. It quickly became apparent that the solution suffered from significant technical challenges.

Migration to Java-based Centile Platform

I initiated a comprehensive migration project, moving GoIP's solutions and customers to a more robust and scalable Java-based platform, Centile. This migration required meticulous planning and execution to ensure correct routing of incoming and outgoing calls between the old and new systems and accurate collection of CDR data for billing.

Replacement of Asterisk Gateways and Implementation of IP Telephony

The old Asterisk gateways were replaced with more advanced ISDN30 gateways. CDR data was collected and distributed through new routines, including to CallMe's billing services. Internal ISDN30 lines were discontinued, and all telephony was converted to IP telephony through IP to ISDN30 gateways.

Development of Virtual PBXs and IVR Call Flows

For customers, I converted solutions to virtual PBXs on the Centile platform. I developed dynamic IVR (Interactive Voice Response) call flows that could be controlled via databases and easy web-based administrations. For CallMe, I also redesigned the internal IVR flows to include self-service, theft blocking, balance control, and more.

A Complex and Critical Migration

This migration was one of the most complex and critical I have handled. In telephony, downtime or interruptions are unacceptable. The security aspects of IP telephony also proved to be a significant challenge, but one we overcame with care and expertise.