SIP Trunk

By replacing traditional ISDN before the planned shutdown, SIP trunks provide your business with flexible, stress free and cost-effective communications delivered over the internet.

The big switch off from BT has already begun, and from 2025 all UK businesses will need to have migrated to SIP. ISDN will no longer be available after 2025; why leave it until the last minute, speak to Red Rock and get your ISDN circuits migrated now.

Using SIP Trunking to Connect to a Phone System

Here at Red Rocks Communications, we'll help you connect your current on-premises PBX to a new SIP trunk and project manage the number port as part of the process. Be it a legacy system that doesn’t support SIP or a modern PBX that does, Red Rock can provide the solution that fits your business.

Internet and SIP

Deploying SIP? Worried about the quality of your internet and its ability to deliver a business-grade service? We’ve seen it before; the client deploys their shiny new SIP trunks over their dirty old ADSL circuit, and they have nothing but problems.

Don’t worry. Speak to Red Rock, and we can guarantee you’ll be given the right advice and solution to provide the levels of service your business needs to operate in the digital world.

Rest assured, the Gamma network has been developed from the ground up to deliver business-grade call quality over its QOS enabled network. Why not bundle in a QOS enabled internet circuit to deliver your new SIP calls in the best possible way.

The benefits of replacing your current system from ISDN

  • Entry
  •   Calls charged at standard rate
  •   Rolling Contract
  • £5.50
    Per SIP Trunk

  • Standard
  • 5000 minutes per channel to 01, 02 & 03 numbers
  • 2000 Minutes to UK fixed Mobiles per channel on 36 month contract
  •   Standard Resilience
  • 12/36 Month Contract
  •  FREE fraud protection
  • £9.00
    Per SIP Trunk

  • Premium
  • Unlimited calls per channel to 01, 02 & 03 numbers
  •   2000 Minutes to UK fixed Mobiles per channel on 36 month contract
  •   Enhanced Resilience
  • 12/36 Month Contract
  •   FREE fraud protection
  • £12.50
    Per SIP Trunk

  • Premium Plus
    SIP Trunk Call Manager
  • Add on to Standard and Premium packages
  •   Web Portal & Mobile Application
  •  12/36 Month Contract
  • Call Management
  • Guaranteed Business Continuity
  • Never Miss a Call!
  • £50.00
    Per SIP Trunk


Frequently Asked Questions

Got any questions? See our SIP FAQ
1What is SIP and SIP Trunking?
SIP stands for Session Initiation Protocol. It is a standard for signalling and controlling multimedia connection sessions. On the other hand, SIP trunking is a way to deliver voice and video communications over the internet.
2Is SIP the same as VOIP?
SIP calls are not the same as VOIP (voice over IP) calls. VOIP is any type of voice call made over the internet, whilst SIP is one protocol used to achieve VOIP.
3Why do businesses use SIP trunking?
Most businesses opt for SIP trunking because of its cost-effectiveness and many disasters recovery options. When using SIP trunking, you pay a lower monthly fee for a far superior solution.
4Is the sound quality for SIP calls good? 
One of the fears you might have when switching from ISDN to SIP calls is that the audio quality might be poor. Thankfully, you don't have to worry about audio quality because SIP providers leverage a tier-1 network with high powered routers. That's why SIP calls sound quality is up to par with calls made over a traditional phone line.
5Bandwidth requirements?
To access SIP calls, you'll need to ensure you have the proper bandwidth. As an industry best practice, you should therefore reserve at least 64 kbps (kilobytes per second) for each SIP call. We can even do this for you in a network.
6How many SIP trunks will a small business need?
Once you know how many calls your business makes daily, it'll be easy to determine how many SIP channels your small business will need. Talk to us, and we’ll quickly be able to give you a good idea, and better still, we can monitor this in future and advise if you need more or even less SIP trunks.
7Network requirements
Your network needs to be adjusted to allow SIP traffic. In addition, it needs to be configured to the optimum setting so that SIP can perform at the best level. Red Rock are specialists in a wide range of routers and firewalls and will be happy to assist in setting this up. In addition: The latency for your network should be 150ms at the very least. Your internal network jitter should be less than 100ms. If your network is not ready for SIP, the call quality won't be good. Are you worried about your internet quality for SIP calls? There is always a thread of other applications sharing your Internet, which reduces your Internet quality. If you need to make a SIP call and this keeps happening, you can dedicate a private internet connection that's reserved just for SIP calls.
8Need a reliable SIP Trunking solution?
Fill out this form, and we'll be in touch to see how we can help. Alternatively, you can give us a call on 0161 470 6212.

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