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SIP Voice Approved Circuits

SIP Voice Approved Bearer Circuits
Spitfire Business 2Mb 1:1 SDSL – From £49.00 per month (for use with Spitfire SIP trunks)

Spitfire have the widest range of SDSL available on the market today. As a Business ISP we understand the key requirements for businesses of all types. SDSL is symmetric broadband – providing the same upload and download speeds.

Bearer circuit requirements


Key requirements for voice Internet bearer circuits include the following:

  • Symmetric upload and download
  • Low contention
  • Reliability
  • Resilience and back up options
  • Guarantees on jitter, latency and packet loss

Spitfire SDSL meets all these requirements and combined with our knowledgeable, specialist staff is the preferred choice for UK SDSL.



Our prime SIPStream® range consists of a 2Mb uncontended (1:1) SDSL circuit – combined with an ADSL circuit for the unbeatable price of £49.00 per month. This will allow you to carry up to 14 simultaneous calls with no degradation in call quality. Including SIP Trunks and Number Provision this allows us to deliver ISDN30e service at a saving of up to 50%. (Please note that when using our SDSL circuits for other purposes the monthly rental charges start at £99.00, still an outstanding monthly cost.)


We also offer Premium ADSL2+ or ADSL Max at a cost of £29.00 – not to be confused with inferior ADSL2+/Max products that only give you an upload speed of 448Kb.

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