UK SIP Trunks

SIP stands for “Session Initiation Protocol” and is a way internet based phones connect to each other in order to provide an audio service – or telephone service over the internet. A SIP Trunk is the service, like a normal telephone service with landlines and has one master telephone number. a SIP channel is like a line on a phone service – or more like the lines you’d get on and ISDN service. So the more SIP Channels you have, the more simultaneous calls you can make and receive. So you’d have a SIP Trunk for your business with several SIP Channels associated with it, to allow multiple calls.

SIP Gateway and SIP Server are often the same thing, but can be different. SIP Gateway is the route your SIP Server (or SIP PBX) might use to connect various types of calls. A SIP Server is usually the actual server which manages your PBX VoIP system – but is sometimes used to describe your SIP gateway Provider. For example you might have a SIP Server (or SIP PBX or VoIP PBX server) – like 3CX or Asterix – which has multiple SIP Gateways from companies like us that you might route different calls types through either for resilience or for cost or service benefits. So if you were based in the US or India for example, you might have a SIP Gateway for Inbound and outbound UK calls, and a different one that handles calls to and from ASIA. SIP is useful that way, allowing you to utilise the internet to make the best choices for which SIP Gateway Provider to use.

SIP channels are effectively the number of “lines” you have, the number of simultaneous incoming and outgoing calls. It varies for each business, but a general rule is 4 staff per SIP channel. For businesses or departments that are heavily phone-based, like a support team for example, you might want one SIP Channel per staff member because they need to potentially be on the phone all the time.

Yes, you can add SIP channels at any time easily, just let us know and we’ll activate them straight away. Added SIP channels do not restart your minimum contract either, the minimum contract period is per SIP Trunk – so you can keep costs down if you expect to grow for example.

Certainly. As our VoIP and SIP network is UK based we’re well placed to handle your calls to and from the UK – especially with our inclusive UK and UK mobile minutes in all of our SIP services. Our network is multi-honed and well connected all around the world, so the call quality and “latency” is low from every corner of the planet. Our reliable SIP Service is extremely popular with non-UK businesses looking to reduce SIP costs.

Our SIP trunks services are all 12 month minimum contracts, payable monthly or annually. Annual pre-payment is the cheapest and the best way to buy SIP services but we’re happy to spread the cost monthly for you too. We require 1+1 months pre-payment for monthly contracts and a credit card or DD on file at all times to ensure your SIP service is maintained.

Yes, our UK SIP trunks and SIP channels are fully compliant and work with all SIP software and SIP clients, including 3CX and Asterix.

Calls to UK numbers starting 01, 02, 03 and 07 are included free of charge with no limitations on call length subject to our Fair Usage Policy.

Our Fair Usage Policy only requires that for us to continue your free outbound calls, that at least 25% of your calls are inbound of a maximum of 75% are outbound. For the vast majority of companies, this is usually a 50/50 split anyway – or leaning towards more inbound minutes than outbound. We only do this to protect our low prices and to ensure the SIP services are not used by auto-dialers or call centres which only do huge numbers of outbound only calls (or mainly outbound). As we still have to pay for call minutes with telecom partners we connect with, and pay for the outbound bandwidth etc – if our low cost bundles were used in this way, we’d have to increase the prices for everyone.

Yes, for call centres or auto-dialer services that would not fit within our FUP, we can quote for minute bundles starting at 5,000 UK minutes per channel.

Sometimes you might find you make an extraordinary amount of outgoing calls for one reason or another, which is fine, we’re happy to let it slip once or twice a year – it should all balance out generally and no harm done. However, for 2 consecutive breeches, or 3 in a year, we reserve the right to terminate the bundle minutes and charge our standard minutes rate for all calls retrospectively (1p for landline,5p for mobiles). But you shouldn’t ever accidentally find yourself here, you’ll know from the outset if more than 75% of your calls are outbound generally.

Our SIP trunks are very reliable and come with as 99.9% uptime guarantee. Whilst we can provide bespoke failover services like redirect or voicemail on the SIP channels themselves, this is normally the job of your SIP Server or cloud-based SIP software. Our Hosted 3CX service for example, provides failover service on the SIP client end, which is the most likely to suffer a failure.

Yes, almost always considerably cheaper. ISDN or PSTN lines usually cost more in rental than our SIP services, and then you have old-fashioned call charges to pay (and even “connection charges” sometimes!). Typically using SIP trunks is at least 20% cheaper but most businesses find themselves saving 60% or more on their telephone costs – especially with our inclusive SIP bundles.

There’s some sites and services that claim that SIP Trunks are made up out of thin air as an excuse for telecoms companies to regain revenue from losing the traditional PSTN and ISDN services (when they are phased out over time, by 2025 in the UK). Whilst a small part of that is true: SIP to SIP calls do establish a connection freely over the internet and you do not need a paid for SIP provider for those. However a SIP gateway service like ours does more than single SIP to SIP, it acts as a routing and middle-man for SIP sessions (calls), connects to other SIP providers in faster and better ways than just relying on the internet, and most importantly, provides SIP to PSTN/ISDN calls (which still cost money per minute). So no, a proper SIP provider has lots of costs associated with providing the SIP Services. Usually the ones claiming it to be a “made up” thing, are doing so to convince you either to pay for SIP calls individually with them or to cover their costs in hidden ways…. Our SIP Trunks are great value!

There are some “Free” SIP services out there, but they all charge you somehow in order to cover their costs, and often skimp on things like call quality, network reliability and support. You’ll generally get these charged on a PAYG basis per minute, often with high prices for mobiles and international calls. With our call-inclusive SIP trunks, you won’t get any shocks and pay a single low monthly fee per SIP Channel.

Sure, we’d be happy to lend you a SIP trunk for a few days to test the quality and reliability, subject to availability – just let us know and we’ll set this up for you.