What is SIP Trunking and what are the benefits?

Dylan Pepler

Dylan Pepler

Voice and data connectivity are essential for any business.  It’s equally important to assess the cost of running multiple lines and to understand how much flexibility and control you want. SIP trunking provides a flexible and low-cost alternative to ISDN for inbound and outbound voice calls.

With the news, last year that BT will be switching off ISDN in 2025 now is the time to consider moving to SIP.

What is SIP trunking?

SIP trunking uses Internet Protocol (IP) to enable organisations to place telephone calls through the Public Switched Telephone Network (PSTN).  With SIP trunking technology, voice becomes an application on the IP network.  The business benefits of SIP trunking are numerous and include:

  1. Business continuity

SIP trunking offers a flexibility that is not available through traditional ISDN. Unforeseen circumstances can affect traditional telephone services, such as damage to lines, moving offices or weather issues.  Designed to protect business customers by increasing reliability and survivability during unexpected service interruptions, it provides continuity of service by systematically re-routing incoming calls to other offices, voicemail boxes or employee mobile devices.

  1. Cost savings

With a traditional telephony service, your organisation is subject to often expensive local, long distance and international calling. SIP trunking allows instant access to simple, understandable pricing through predictable monthly costs, generally billed on a per-user basis.  It can typically save you a further 50% on line rentals and 25% on calls as it allows you to make free calls between connected sites, even internationally.

Without capital investment, organisations who switch begin appreciating cost savings from the first monthly billing statement.


the business case for SIP ebook

  1. Scalability and flexibility

If you’re still using ISDN, the chances are that you’re purchasing more phone circuits than you really need and therefore over-engineering your phone systems. SIP trunking’s single-increment scalability gives you complete control of your lines: you can add more when demand is high (such as seasonal demand), reduce them when there is little demand and split calls to make handling more efficient.

  1. Number flexibility

SIP trunking supports your business by allowing you to decide which number you want to display on a call-by-call basis. It allows out-of-area geographic number ranges to be used, displaying your number as a local business, even if you’re physically located elsewhere.

  1. Mobility

SIP allows your organisation to connect your employees’ mobile devices via flexible, user-friendly VoIP apps that can be securely installed. Mobile workers can remain connected to your on-premise based communication systems and fully reachable at all times via a single, dedicated business phone line.

  1. Unified Communications enabler

SIP trunking can be a huge enabler of the adoption of UC strategies, allowing you to unlock the benefits of an IP-based communications suite.  Combine all of your varied communications needs – whether email, instant messaging, voicemail, video conferencing, and every day telephony– into a single, manageable strategy.

  1. No more physical infrastructure

In a multi-site environment, SIP trunking eliminates individual telephone circuits at each location, consolidating them into one centralised site, resulting in reduced hardware and significant cost savings over time.  You can add phone lines or add-on services by simply connecting handsets to your data connection and scaling your monthly service agreement.

Is SIP trunking the right choice for your business?

While SIP trunking offers significant cost savings, reliability and flexibility, it requires sufficient data connectivity bandwidth to work effectively.  More and more businesses are beginning to realise that it’s is a viable solution for their communications needs.

Contact Blackstar Solutions on 0333 1232123 or email [email protected] to find out more about SIP trunking and how you can move your business communications to the cloud.