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Reference
Telecoms terms in plain English
The vocabulary networks use, translated. Bookmark this page and no contract page or support chat need be confusing again.
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A–Z
| Term | Plain-English meaning |
|---|---|
| 4G Calling / VoLTE | Carrying voice calls over the 4G layer instead of older networks — clearer calls, better indoor reliability. |
| 5G standalone (5G+/SA) | 5G running on its own modern core rather than leaning on 4G. Faster response; smallest coverage footprint. |
| Deadlock letter | A network's written admission it cannot resolve your complaint — your ticket to the free ombudsman before 8 weeks pass. |
| eSIM | A SIM downloaded as software into your handset instead of a plastic card. |
| Fair-use policy | The fine print limiting "unlimited" or "inclusive" features — data abroad, endless social data, international minutes. |
| MVNO / virtual network | A brand selling plans over another operator's masts — e.g. Tesco Mobile on O2, SMARTY on Three. |
| Not-spot | A location with no usable coverage from a given network — increasingly targeted by satellite messaging trials. |
| OTP | One-time passcode texted to confirm it is really you. Never share one with any caller, ever. |
| PAC | Porting Authorisation Code — moves your number to a new network. Free by texting PAC to 65075. |
| Roaming | Using your phone on foreign networks. Terms vary sharply by plan since UK–EU rules changed. |
| SIM-swap fraud | Criminals hijacking your number onto their SIM to intercept security codes. |
| Spend cap | A bill limit you set with your network — the best protection against surprise charges. |
| STAC | Service Termination Authorisation Code — closes your line without keeping the number. Free by texting STAC to 75075. |
| Text-to-Switch | The Ofcom-mandated system letting you leave a network with one free text. |
| Wi-Fi Calling | Ordinary calls carried over your broadband when mast signal is weak. Free on major networks. |