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Hosted IP Phone Systems

Cloud Hosted IP PBX

Our software-based open standards IP Phone System offers complete Unified Communications (UC) out of the box. See who is on the phone with Presence, use chat to reach your colleagues, instantly setup Conference calls at the touch of a button. Never miss a call with Android and iOS clients.
All of this hosted in a secure 24/7/365 state of the art data centre, ensuring maximum uptime and true HD quality voice.

  • Slash telco & communication costs – Free calls to UK Mobiles and Landlines
  • Boost productivity with UC: Presence and Chat
  • Work on the go: Android and iOS clients
  • Integrated WebRTC Video Conferencing
  • Improve Customer Service: Click2Call & CRM Integration
  • Installed in The Cloud – no hardware needed on site

“The end of ISDN & PSTN”

What does the end of ISDN mean for UK businesses?

BT has announced a target date of 2025 for completing the migration of all ISDN and PSTN customers to IP.
As BT continues to plan for the decommissioning of its ISDN infrastructure, its replacement, SIP, is a hot topic for IT leaders. SIP is now a well-established technology and is the preferred solution for businesses of all sizes, in many ways outperforming ISDN.

ISDN is a robust and reliable technology. How does that compare with SIP offerings?

It’s true that ISDN is generally a reliable service but it’s worth remembering that the phase out of ISDN is a certainty, so, over time, BT’s investment in the technology will diminish. The network will no longer be developed so is likely to become less reliable. The number of engineers trained on ISDN will decrease, availability of spares and parts on telephone systems will become difficult to obtain and the support experience is likely to deteriorate. It’s inevitable that, for businesses looking to invest in the future, ISDN will present limited choices.

Office Without Limits

Make calls anywhere using Android, iPhone, Mac & Windows

With our VoIP clients for Android and iOS you can take your extension wherever you go. We deliver a one number concept meaning that you no longer have to give out your mobile number. We can set your status so your colleagues can see whether or not you are available to take a call.

  1. Make and receive calls from your smartphone – at no costs
  2. Set your status to available, away and out of office from your smartphone
  3. One number concept
  4. See the presence of your colleagues from anywhere


You are free to select your desk based SIP Phones that suit you and are not tied into any specific manufacturer. As well as desk phones DECT and Conference phones are all available.

Why ISL for my IP PBX?

We provide the hardware, SIP Phones and Headsets

Single call to ISL for IT Support = fast resolution

Experts at migrating clients with no loss of service

We have a state of the art IP PBX UC Solution– suitable for 5 to 500 users

We host the PBX in our secure Data Centre

We provide the SIP Trunks

We retain your existing phone numbers

We can offer FREE UK mobile and landline calls

20 years of experience in the voice market

Book Your FREE On Site IT Assessment Today

We are offering a completely free On Site IT assessment worth over £1000.
Carried out by our expert IT Business Analyst team with over 25 years’ experience.
We will provide you with a full review and strategy designed to suit your business.

Why choose ISL?

Over 20 years of exceptional Hosted IP Phone Systems
Local in Hertfordshire, Bedfordshire, Buckinghamshire and London
ISO27001 Information Security Management Certified

ISL part of the Wavenet Group Logo

ISL part of the Wavenet Group Logo

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The British Assessment Bureau ISO-27001
The British Assessment Bureau ISO-27001