Modernising voice: the move to IP

Get closer by migrating TDM to SIP

In a workplace in the throes of digital transformation, with disruption affecting companies in all sectors, IT leaders and business unit executives are working to determine how best to enable employee agility, collaboration and engagement.

The consumerisation of the work environments, driven by the expectations we have from suppliers in our personal lives, is placing collaboration options such as Unified Communications (UC) and video into the hands of more enterprise employees than ever before. This allows enterprises to accommodate a greater pool of employees and other participants, as well as to support a greater range of use cases, including support for remote users, mobile users, and distributed teams.

This same trend is driving the modernisation of networks, the upgrade to current-generation technologies and the retirement of outdated technologies such as TDM.

For decades TDM voice infrastructure has proved a robust and reliable asset. But in recent years the technology has been challenged by SIP (Session Initiation Protocol) and VoIP. As the supplies of TDM equipment are gradually depleted and the skills to maintain the equipment cycle out of the market, costs of maintenance and management are increasing, while the features and capabilities offered by VoIP continue to grow.

In fact, statistics from TeleGeography tell a story of shrinking international call growth rates over the last decade, suggesting voice communications are moving to alternative mediums, with TDM voice minutes declining in the face of increased IP traffic.

Indeed, many analysts have said that “digital first” or “digital to the core” is now a crucial part of the strategy of many organisations, but these initiatives require an agile, reliable infrastructure. Legacy networks aren’t optimised for digital business and enterprises are advised to modernise their networks now and replace legacy technologies that cannot keep pace with changing requirements.

One option is to upgrade to improved current-generation network capabilities and retire outdated technologies like time division multiplexing (TDM) and ISDN.

But it’s not always possible or straightforward to make such transitions, especially in an increasingly complex hybrid IT environment. In these instances a bridging solution is often needed to allow organisations to transition to the next generation of technology that fits with their wider IT transformation strategy.

For those still relying on ISDN and still some years away from adopting VoIP/SIP completely, we have the capability to deliver ISDN over SIP. Colt ISDN over SIP combines traditional ISDN infrastructure with modern SIP trunking delivered over the Colt IQ Network.

This provides the opportunity to transition easily from both a commercial and technical perspective to SIP trunking when the enterprise is ready. Delivering a future proof VoIP-based ISDN telephony service with more features than traditional TDM voice. All without having to invest in your own IP network.

Business impact: SIP trunks can reduce the costs associated with remote call forward, virtual foreign exchange (FX) configurations and intrastate long distance. They can deliver added flexibility by providing a path for better integration of communications channels. Customers with a high concentration of on-net traffic or high volumes of voice concentrated in large sites can save up to 40% on recurring access fees and voice rates (Gartner).

User advice: Adopt SIP trunks as a replacement of ISDN access services in order to save money and deliver greater flexibility of in-house PBX or UC deployments. Evaluate suppliers based on offer maturity, local service coverage, customer premises equipment (CPE) and service/feature interoperability, backward integration with legacy services, simplified billing, and SLAs.

To discover how Colt ISDN over SIP can bridge the gap between TDM and VoIP, download our white paper ‘’Modernising voice: the move to IP’’ here.

Veerle Van Hemelrijck is Product Manager, ISDN Voice at Colt

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