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.

Simple 30 day rolling contracts on all Business SIP Trunk UK plans. Terms are monthly in advance with credit card or DD setup on file. You can also pay annually in advance which equates to a 15% discount. SLA’s up to 3 years are available on request.

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

On our Unlimited SIP plan, calls to UK numbers starting 01, 02, 03 and most 07 (mobile) are included free of charge with no limitations on call length subject to our Fair Usage Policy. Mobile calls are only free from the major Tier1 providers: O2, Three (H3G), Vodafone (inc CW), Orange and EE. All other “mobile” calls are charged.

On our SIP Unlimited plans our FUP is very generous and designed to ensure all normal business/organisation users have all of their UK Geographic and UK Mobile calls included without additional charge. This is a soft limit of between 1500 and 2500 minutes per channel per month – which is 99% of all of our current users comfortably. We do monitor usage and very high users (like outbound call centres) will be moved to our fixed 4000minute plan where appropriate. Keeping our Unlimited plan essentially unlimited for every user is very important.

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 automatically move you to a fixed bundle plan and charge any excess calls. This really does very rarely happen, for 99% of all businesses, the FUP is more than enough.

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.

No, we fully manage the migration process for you to ensure no downtime. The SIP service should be setup in advance so that as soon as the numbers flip, they route to your new SIP PBX. When switching SIP providers, running both your old and new SIP trunks side by side during the 7-14 day transfer window is the safest method to ensure no lost inbound calls and fully operational outbound

There are some “Free” SIP services out there – and some with very low monthly fees (or so they appear!, 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. We try to offer good value but don’t skimp on service features and quality.

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.

Yes, although we’re not on the default supported list of providers in these versions, we have a simple way to get our SIP trunks working with both of the 3CX SMB and 3CX 4SC Free versions – just let us know when you order and we’ll send instructions.