Clear answers to the questions businesses ask before choosing a number, SIP trunk, hosted phone system, 3CX route, call package or number port.
Each guide includes a direct answer, practical checks, visible FAQs and links to the official sources used to verify important claims.
A UK 01 or 02 number can be routed to a team outside the named area in permitted circumstances, but the area code retains geographic significance. The customer should deliberately request that area code, the call must retain the expected geographic tariff treatment, and marketing should not mislead callers about a physical office.
Read the guide →Choose a SIP trunk when you already operate a compatible PBX or 3CX platform and want a provider connection for numbers and calls. Choose hosted VoIP when you want the phone platform, extensions and management delivered as a service. The right answer depends on who owns the platform, who supports it and how much control your business needs.
Read the guide →Use 01 or 02 when geographic identity matters, 03 when you want a UK-wide number charged to callers like a geographic call, and 0800 when you want the call to be free for the caller. The receiving business may still pay service and inbound-call charges.
Read the guide →Number porting lets a customer keep an eligible telephone number when changing provider. The gaining provider submits the request using matching account and number details. Do not cancel the existing service before the port is accepted, and check whether broadband, alarms, payment terminals or other services depend on the old line.
Read the guide →Yes. A UK business number can forward to a mobile, ring a mobile application through hosted VoIP, or use a phone system that rings desk and mobile devices. The best method depends on call volume, caller ID, voicemail, reporting, opening hours and the cost of forwarded calls.
Read the guide →Size SIP capacity by simultaneous calls, not by the total number of employees. Count the highest expected inbound and outbound calls during the busiest period, include queued or transferred calls where the platform uses a channel, then add sensible headroom and monitor real usage after launch.
Read the guide →A number is not 3CX-compatible merely because it can be delivered using SIP. Confirm the provider method, authentication, source identification, DID format, inbound routes, outbound caller ID, codecs, firewall rules, simultaneous-call limits and support responsibility before migration.
Read the guide →The total cost is normally a combination of one-off setup, monthly number rental, phone-system or SIP capacity, optional call packages, outbound usage and any forwarded or Freephone inbound calls. Compare the complete call path and billing unit, not just the headline monthly price.
Read the guide →Choose a number that customers can recognise, repeat and keep using. Area relevance and clear digit patterns are useful, but the number must also suit the long-term service, routing, call volume and brand. Do not imply a physical location that the business does not have.
Read the guide →Choose a single number for one main route, campaign or small team. Choose a DDI block when several users, departments or services need distinct public numbers that route through the same SIP trunk or phone system. Plan the full range before ordering or porting.
Read the guide →Understand the terminology used across DDI numbers, hosted telephony, SIP trunks, 3CX, call forwarding and number porting.
Read the complete overview →These pages answer a defined customer question, distinguish facts from buying advice and link to Ofcom, GOV.UK and official platform documentation where appropriate. They are not generated town-and-keyword doorway pages.
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