fernwick
Independent · United Kingdom mobile networks · guidance only
Advisory line 020 3896 5248 This line is for guidance and information only. We sell nothing, arrange nothing and act for no provider. If anything on this page is unclear, telephone and we will explain it.
Advisory note AN-19

Terms explained

The vocabulary used across this advisory, in plain words, grouped by where each term turns up.

Note AN-19 · three sections · reviewed July 2026 · no prices published

Independent status. fernwick is an independent guidance and information service. We are not a mobile network. We are not affiliated with, endorsed by, appointed by or connected to Three, EE, O2, Vodafone, Sky Mobile, Tesco Mobile or any other provider, and we hold no commercial arrangement with any of them. We do not sell, supply, arrange or broker SIM cards, contracts, handsets or services of any kind, and we take no commission. Everything published here is general information and must not be relied upon in place of the provider's own current terms.
Our position in one line

About twenty terms carry the whole of the small print — and most of them are plainer than they sound.

§1Moving between providers

TermPlain meaning
PACThe free code, texted to 65075, that carries your number to a new provider within thirty days
STACThe same idea (75075) where you would rather drop the number and start fresh
PortingThe behind-the-scenes transfer a code sets off, usually done within one working day
Final responseYour provider's formal end of a complaint — and your immediate ticket to the ombudsman

If any of this is unclear

Telephone the advisory and we will talk it through. There is nothing to buy at any point.

020 3896 5248This line is for guidance and information only. We sell nothing, arrange nothing and act for no provider. If anything on this page is unclear, telephone and we will explain it.

§2Signal and calling

TermPlain meaning
4G Calling (VoLTE)Voice carried over 4G. Needed since 3G closed on every UK network
Wi-Fi CallingCalls and texts over your home broadband — the free fix for a bad room
Standalone 5G5G on its own modern core rather than leaning on 4G. Quicker where live; smallest layer
CongestionToo many handsets on one mast. Full bars, no throughput — and not a coverage problem

§3Money and small print

TermPlain meaning
Fair-use ceilingThe published limit hiding inside an 'unlimited' allowance, mainly abroad
TetheringSharing your handset's data with a laptop. Capped on some plan generations
Split contractHandset credit and airtime billed separately, so device payments stop at repayment
Spend capA free limit you set yourself to prevent charges beyond the allowance
MVNOA brand renting masts rather than owning them
7726The free number for forwarding fraudulent texts to providers' fraud teams

Speak to the advisory

Telephone the advisory and we will talk it through. There is nothing to buy at any point.

020 3896 5248This line is for guidance and information only. We sell nothing, arrange nothing and act for no provider. If anything on this page is unclear, telephone and we will explain it.
Independent status. fernwick is an independent guidance and information service. We are not a mobile network. We are not affiliated with, endorsed by, appointed by or connected to Three, EE, O2, Vodafone, Sky Mobile, Tesco Mobile or any other provider, and we hold no commercial arrangement with any of them. We do not sell, supply, arrange or broker SIM cards, contracts, handsets or services of any kind, and we take no commission. Everything published here is general information and must not be relied upon in place of the provider's own current terms.
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