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Explaining SIP Trunking, the Ultimate VoIP Solution

Explaining SIP Trunking, the Ultimate VoIP Solution


Before internet telephony was a thing, businesses in need of a professional phone system that’s capable of distributing incoming calls to every phone connected to the same system had no choice but to install an on-site private branch exchange (PBX). Granted, a PBX perfectly serves its purpose even to this day, but its maintenance is a nightmare from both a technical and financial point of view.

SIP trunking

So it’s not surprising that many businesses have decided to move their phone traffic to the cloud. The only problem is that leaving the old system behind – with a carefully set up PBX – often means starting anew. Thankfully, VoIP has this problem covered with SIP trunking, a service that integrates existing PBXs into your new cloud phone system.

SIP trunking vs regular VoIP

Admittedly, it’s easy to confuse regular VoIP services with SIP trunking because both rely on voice traffic over the internet, however there are still some key differences. For instance, a VoIP service provider offers a direct connection to the public switched telephone network (PSTN) and assigns each business with a hosted PBX that is only loaned to them while they remain an active subscriber.

Spit trunking and Hosted Cloud PBX

SIP trunking, on the other hand, always requires users to use their own PBX to connect their phones to the PSTN. At first this seems like a nuisance, however this is actually quite beneficial as businesses can keep any existing hardware without the need to adjust complicated settings and still enjoy everything associated with a VoIP service – such as the wide variety of call handling features and streamlined management systems with the added pleasure of more cost-friendly prices.

The advantages of SIP trunking

Letting users keep their on-premise PBX is indeed a great feature of SIP trunking. However, this is just the tip of the iceberg as this service has many other advantages up its sleeve.

For starters, a system using SIP trunking is fully scalable, meaning that additional features can be added or removed depending on the current needs of the business without having to install any additional hardware – which is something that alternative options to SIP, such as the typically safer Primary Rate Interface, are incapable of. Another huge advantage of SIP trunking is that it provides users with the option to place and receive multiple calls at the same time without the need for purchasing additional phone lines, as well as enabling free calls between any office using the same VoIP service.

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However, perhaps the best feature by far coming from using SIP trunking on existing PBXs is that this method unifies all communications, meaning that everything from voice, video and any other type of traffic will flow through just one channel, which is then distributed in an automated and intelligent manner. Simply put, SIP trunking reduces the number of necessary networks to just one, which is not even bound to a single physical location as the phone system can be accessed from anywhere that there is a sufficient internet connection.

To make things even better, a PBX with SIP trunking is failproof: the PBX will be continuously maintained by the service provider but they will also make sure you can still place and receive calls as if nothing happened, even if the main service is experiencing problems.

Is it for me?

Although SIP trunking is indeed a great way to reduce costs – particularly when it comes to the maintenance of an on-site PBX – but unfortunately it’s not for everyone. The biggest and most obvious limitation by far is that in order to activate this service the business should possess a PBX to begin with. In addition to that, the PBX needs to be SIP-enabled already; manufacturers only release the latest PBXs with this feature on board, but even that cannot guarantee a PBX’s interoperability with VoIP services.

Still, all VoIP providers that offer SIP trunking services – like RingCentralNextiva or VirtualPBX – are known for being flexible when it comes to finding the ideal solution for integrating your PBX into the new phone system, while also keeping costs as low as possible. But if that doesn’t succeed, remember: these companies also provide advanced hosted PBXs that can be set up in the same way that your old PBX can. And abandoning an existing PBX in favor of a hosted one is still better than being left with a PBX that cannot work in the cloud.


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