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What do I need to know about SIP?

September 25, 2018

What do I need to know about SIP?

Written by Atlas Comms

What Actually is SIP?

In basic terms, SIP (or Session Initiation Protocol) is a common language used in technology as a way of communicating between devices. It is an ‘open standards language’ meaning it is not manufacturer specific.

A good way to think of it is in terms of language. For example, someone whose first language is English may also be able to speak French and German, meaning they can communicate with more people than solely English speakers. However, more than likely 2nd or 3rd languages will not be as strong as their English communication skills, which can limit conversation, i.e. SIP does not eliminate the benefits of manufacturer specific communication, but it does open up more options & adds flexibility by enabling communication with multiple different devices.

If you have not heard of SIP, you soon will because it is fast becoming the standard for provision of office telephone lines so will impact businesses of all sizes as the new technology takes over from ISDN lines.

The Jargon Problem

As ever with technology, confusion has emerged over what SIP actually is in the context of telephone lines. If you think of SIP lines (or trunks) in the same way as your current phone lines with regards to functionality then you have 90% of the answer. The difference however lies in how those lines are provided and how you access them.

With ISDN, your lines are brought into your office on very distinct copper cable solely for the provision of telephone lines. Other cables bring you your Internet. With SIP, the lines don’t come to you, you go to them. (Usually via your Internet connection.)

In practice for the user, it's simple - when they dial a number using a SIP line or when they receive a call from outside the office, they do so exactly as they would with ISDN lines. The difference being the infrastructure working in the background to carry the calls.

Benefits of SIP

SIP Trunks do everything regular ISDN and PSTN lines do, but there are some additional benefits for businesses:

  • Cost
  • Flexibility
  • Non-Geographical

Cost is definitely a contributing factor in the move to SIP. Monthly rental charges for traditional ISDN lines can be anywhere from £11-15 but with SIP Trunks, monthly rental can be half that. Communication costs are also cut down as there are now so many SIP Trunk providers and this competition has driven down call charges significantly. Some SIP Trunks even come with unlimited calling, meaning you can save on international call charges, too.

However, it is important to remember that you may need to also factor in the cost of an Internet connection for SIP Trunks, if your current service isn’t strong enough to support it. Speak to your service provider for more information.

SIP is fast to deploy and you can easily expand it to cope with increased calls. Often this can be done immediately, compared to the delay in having additional lines installed and then having to upgrade your old PBX to handle more lines.

Also, connecting an IP PBX to SIP Trunks is much easier than via the PSTN. You can go on premise or hosted, the choice is yours.

SIP Trunks are also non-geographical meaning you can provide better customer service by adding geographical and international numbers. You give customers more options to dial in at a significantly lower cost, even long distance. Customers can contact you more easily and sales will hopefully increase.

As SIP Trunks are not bound to a location, it is easier to move offices. There is no longer any need to pay to forward phone calls to new premises, or to inform customers & update company website, stationary etc.

What SIP is not

There are a lot of new technologies and terminologies being used within telecoms these days especially as we move away from on premise products. As such, it is also important for organisations to understand what SIP is not:

  • SIP is not VoIP (but may be used as part of a VoIP telephone solution)
  • SIP is not Hosted telephony* (though may be used as part of a hosted solution)
  • SIP is not the Internet (and doesn’t necessarily need the Internet)

VoIP is a wide and expanding industry allowing calls to be made over internet lines rather than traditional ISDN phone lines. SIP is a part of it & possibly one of the main pillars of VoIP. However, along with SIP, there are a number of other protocols that can be used for voice & video communication. For example, Skype is a well-known VoIP communication solution that chooses to use its own architecture, as do many other service providers.  

SIP is very common in hosted telephony, as a lower cost manner of implementing the solution. This is mainly because you do not require a license, making it quicker and cheaper to deliver.

*For more on Hosted Telephony, visit our ‘Cloud vs In-Premise’ blog here.

Remember SIP is simply the language that is used when devices are communicating with each other. The Internet is just one of the methods that can be used to deliver this communication between devices.

The Countdown to SIP

If SIP has been used within IT for so long, then why is it now so popular within telecoms? The biggest reason comes from the fact that the internet is now simply fast enough to facilitate its use. We have moved on from the days of dial up and can now maximise the many benefits that Ultrafast Internet has to offer. This has led to an increase in convergence – i.e. an opportunity to use the one same road for everything, from data to voice traffic.

Another factor increasing demand currently is BT’s announcement that the trusted old Public Switch Telephone Network (PSTN) and ISDN lines will be switched off in 2025. The big telecom providers are fast phasing out the old PSTN functionality, moving customers to IP telephony and so seemingly, SIP Trunks and a phone system upgrade in the near future seems to be inevitable.

Getting Started

It is important to not be panicked by the cold callers pushing you to upgrade your phone system straight away. BT’s 2025 timeline is simply a guide and no one knows exactly when the cut-off point will be. Major infrastructure works & investment will be needed to ensure that connectivity is ready for the move to IP telephony across the UK.

Your business can take some simple steps now to get ready and spread out the costs of switching to SIP: -

  • Make sure that your current phone system accepts SIP trunks. A rule of thumb is that if a system is older than 10+ years it probably will not be SIP enabled. If you are unsure, email our team and they will be able to tell you straight away
  • If you need to upgrade your system it’s best to find out sooner rather than later, so you’re not being hit with the costs of both the upgrade and SIP Trunk configuration  
  • Consider your current Internet connection and if it is fast enough to support your voice traffic. If not, it might be worth considering a dedicated line only for voice traffic, to ensure that you never experience any downtime. This is particularly important for businesses where the telephone is business critical, for example GP Surgeries
  • Once you have all this in place, it means when the time comes to make the switch to SIP, your installation costs will only be focused around programming & work to get the phone system to send & receive calls through the connection
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