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Kallin sits between your existing UK phone numbers and the people who call them. Rather than replacing your current provider — whether that’s BT, Sky, Virgin Media, Vodafone, O2, EE, or Three — Kallin connects to your numbers and adds a powerful layer of smart routing, management, and visibility on top. You keep your numbers, keep your provider relationships, and gain a single cloud dashboard to control exactly how every call is handled.

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The Connection Flow

1

Add your number from a UK provider

You register your existing UK phone number in the Kallin dashboard. This can be a geographic landline, a non-geographic business number, a mobile number, or a virtual VoIP line from any of the major UK providers.
2

Kallin verifies ownership or ports the number

Kallin confirms that you have the right to manage the number. For numbers you are keeping with your current carrier, this is a quick ownership verification. If you choose to port a number directly into Kallin, the platform handles the transfer process with your provider on your behalf.
3

Calls flow through Kallin's routing engine

Once connected, every incoming call to that number passes through Kallin’s routing engine before reaching a destination. This happens in milliseconds and is completely transparent to your callers.
4

You control where calls go via routing rules

Using the dashboard, you define routing rules that determine what happens to each call — forward to a specific phone, ring a team, play an IVR menu, or send to voicemail. You can change these rules at any time without touching your carrier.

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Number Types Supported

Kallin supports the full range of UK number formats regulated by Ofcom:
  • Geographic numbers (01/02) are tied to specific UK regions and area codes. They are the traditional landline format and carry strong local identity for businesses.
  • Non-geographic numbers (03, 08) are not associated with a physical location. They include business-friendly 03 numbers and Freephone 0800/0808 ranges, making them ideal for national-facing operations.
  • Mobile numbers (07) are allocated to mobile networks across the UK. On Kallin, these can also support SMS-capable lines depending on your provider and plan.
  • Virtual / VoIP numbers have no physical SIM or line behind them. They exist entirely in software, making them perfect for remote teams, cloud-first setups, and flexible deployments.

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Routing Engine

When a call arrives at one of your numbers, Kallin’s routing engine evaluates your rules from top to bottom. The first rule whose conditions match the call determines where it goes next. You can route based on the time of day, the day of the week, the caller’s number, the number that was dialled, or a defined holiday schedule. Destinations can be a single phone number, a ring group (where multiple phones ring simultaneously or in sequence), an IVR menu (where callers choose options), or voicemail. If no rule matches, you define a fallback destination so no call is ever left unhandled. You can update, reorder, and test your routing rules at any time from the dashboard — changes take effect immediately, with no downtime.
Kallin does not replace your existing phone carrier. Your numbers remain with BT, Sky, Virgin Media, Vodafone, O2, EE, Three, or whichever provider you use today. Kallin sits in front of your numbers to add smart routing, management, and analytics — your carrier relationship and billing stay exactly as they are.

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Explore Further

Phone Numbers

Learn about every UK number type supported on Kallin and how to choose the right one for your needs.

Call Routing

Dive into routing rules, conditions, destinations, and time-based logic to master how calls are directed.