What is SIP Trunk?
SIP is just one of the possible “protocols” you can use for VoIP communications. It is similar to how HTTP functions with pages on the internet and provides a way to convert voice signals into data that can be decoded by devices used by a caller.
SIP stands for Session Initiation Protocol and is essentially a way to make an end connection for data and voice transfers over the internet. The ‘trunking’ element is a bit of a red herring, as a trunk used to refer to a bundle of phone lines shared between users. Modern trunking refers to a virtual link between your PBX and the standard phone network (the PSTN), using an internet connection.
Any business with a modern IP PBX (a PBX that supports the use of SIP to transfer data) also needs a way to connect their exchange to the wider PSTN. Traditionally (with older PBXs) this was done using ISDN. Now, with ISDN slowly being phased out, SIP Trunks are becoming the industry standard for connecting business phone networks over the internet.
Who should consider them?
In short, any business! If you already have an IP PBX, you’ll know (or should know) that SIP Trunks are an absolutely essential component. But if you’re new to phone systems or are changing from an analog PBX, you have a choice to make between an on-premise (often shortened to “on-prem” in industry lingo) IP PBX or a full cloud-hosted PBX system.
Using on-premise hardware combined with SIP trunks is particularly suited to businesses with these characteristics:
IT managers and telephony specialists in house
On-premise PBX systems need professionals to set up and maintain them. These can be agencies and managed service providers, but will also need at least one in-house contact with some knowledge of telephony. On-premise PBX systems, combined with relevant setup and maintenance, can be very expensive in the short term.
Significant Call Volume
Any business or site with a high volume of outbound and inbound calls need the flexibility and cost-effectiveness that SIP Trunking provides. Call centers, for example, sales or support hubs, are highly likely to run more complex PBX systems supported by specialist high-volume SIP services.
For these businesses, getting the right SIP provider that fits their calling profile can mean serious cost savings in the long run, with the downside of spending more on hardware and setup in the short term.
For other types of businesses, hosted PBXs may be a better bet, as they allow a similar range of features and reliability with almost none of the maintenance and setup cost of on-premise alternatives. A good VoIP provider should always help you choose the best option to fit your business.