Click here for T300/500 configuration parameters guide

SIP Trunking allows business customers to lower costs, increase resilience with a Disaster Recover strategy, improve flexibility and use multiple new and existing phone numbers anywhere in the UK.

Spitfire are one of the few interconnected operator and Internet service providers. We provision our own SIP Trunk services over our own Internet and Voice networks – a true end to end solution with all aspects of the service managed by Spitfire. In addition to this we also provide SIP Trunks through another leading UK Wholesale Provider – allowing our customers to have two separate SIP Trunk services all managed by Spitfire.

Spitfire SIP Trunks are a genuine alternative to ISDN30e – with us providing a managed service covering the IP connectivity, SIP Trunks and number management – exactly the same as with ISDN30e. We take responsibility from day one for delivering a robust business class SIP Trunking solution.

See more info from their own website here.