SIP Trunking the Cost Effective Alternative to ISDN


A cost effective alternative to ISDN that gives your business flexibility and business continuity.

What is SIP?

SIP (Session Initiation Protocol) is a technology that allows you to make and receive calls using an IP connection, rather than a traditional ISDN line.
It is fast becoming the standard technology, providing more flexibility, reducing costs, maximising investments and leveraging your IP infrastructure.

Why SIP over ISDN?

For any business looking to move premises, change or upgrade data connectivity or replace their telephone system but at a cost reduction yet still deliver remote working and flexibility SIP is the natural choice.  ISDN is a one-dimension application, restrictive, expensive to deploy and as such faces increasing competition from ergc-sip-trunking-imageasy-to-use, flexible and scalable SIP Trunking.

The benefits of SIP are easy to understand and clear. SIP has far more benefits than ISDN; more flexibility, reliability and value. Businesses that fail to replace and migrate from ISDN will become progressively disadvantaged in terms of service quality,  flexibility, responsiveness and profitability.

Not all SIP service providers are the same – application access, features and most importantly platform reliability are different. SIP can’t work without a data connection, one of the choices to consider is the right access network.

The Benefits of SIP

The lack of legacy integration meant no compromise to our SIP network.  Use our network to deliver calls and services when and how you want them. Plus, logic within our network responds and protects to changes from either loss of service or outage.

As the withdrawal of ISDN has been announced, voice networks move more and more towards SIP.  It is the cost effective alternative to ISDN and delivers far more benefits than ISDN. Please see “The Future of ISDN Communications”

Converged Voice & Data Network

Converged ButtonCentralise your PSTN access. Use a single network for high quality voice & data reducing cost yet increasing functionality & bringing modern day flexibility to voice.

Auto Failover & Effective Disaster Recovery

Auto Failover button In the event of disruption SIP makes the process quicker and easier – calls can be immediately re-routed to any other location, backup site or phone.


Reliability button Spread across secure, geo-redundant data centres ensures the highest levels of reliability.

Rapid Deployment & Easy to Use

Rapid Deployment button Rapid and simple setup gets you up and running much quicker than ISDN.


Scalability button Grow or shrink the number of extensions as required on demand. Something not possible with ISDN. Capacity can be added without the need to install physical lines

Fraud Detection

Fraud Button Our SIP products have built-in fraud detection. Protection against fraud is a core part of our service. (A free market leading service as no one should benefit from fraud)

Numbers or Number Porting

Number ButtonSIP isn’t geographically dependent, if you move premises you can keep the same number. Alternatively, we instantly provision and port a variety of UK and international numbers.

Significant Cost Savings

Cost Savings Rationalising ISDN reduces complexities increases efficiencies and simplifies your infrastructure. Consolidate SIP trunks and your network connectivity costs by getting both from us. Plus get free on-net calls.


Call us today on 0330 00 22 222 and see what a difference RGC can make to your business…