What is SIP trunking and do I need SIP trunks for my business phone system?

SIP (Session Initiation Protocol) is the technology standard used to set up, manage, and terminate voice calls over the internet. A SIP trunk is essentially a virtual phone line that connects your phone system to the public telephone network via your internet connection.

How SIP trunking works:

Traditional phone systems use physical ISDN lines or analogue lines to connect to the telephone network. SIP trunking replaces these with a virtual connection over your broadband, delivering the same functionality at a fraction of the cost.

Benefits of SIP trunking:

• Cost savings of 30–60% – SIP trunks are significantly cheaper than ISDN lines, especially for businesses making high volumes of calls
• Flexible capacity – add or remove channels instantly without waiting for physical line installations
• Number portability – keep your existing business phone numbers when switching to SIP
• Geographic flexibility – use local numbers from any UK area code regardless of your physical location
• Business continuity – calls can be automatically rerouted to mobiles or other sites if your primary connection fails

Do you need SIP trunks? If you have an existing on-premise PBX that you want to keep, SIP trunking is the most cost-effective way to connect it to the telephone network. If you are starting fresh, a fully hosted VoIP system may be a better option as it includes SIP connectivity as standard. Speak to our team to find the right solution.