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Reference

Terminology reference

The vocabulary of the sector, rendered into English. Every term a contract page or support conversation is likely to produce.

Published: Northgate Review editorial deskLast reviewed: July 2026Reading time: 3 minutesJurisdiction: United Kingdom

Summary of key points

  1. A PAC retains the number upon departure; a STAC begins afresh — both free by text.
  2. MVNO denotes a brand leasing another operator's masts.
  3. VoLTE conveys voice across 4G — indispensable since the 3G retirements.
  4. A deadlock letter constitutes early admission to the free ombudsman.
TermRendering
4G Calling / VoLTEVoice conveyed across the 4G layer; indispensable since 3G's retirement; found within call settings.
5G standalone / 5G+5G upon its own modern core rather than leaning on 4G. Superior responsiveness where deployed; the smallest footprint.
Deadlock letterThe network's written concession that it cannot resolve a complaint — early admission to the free ombudsman.
eSIMThe SIM as a download rather than plastic.
Fair-use policyThe clause qualifying "unlimited" — abroad, upon hotspots, upon "endless" application data.
Host networkThe physical operator whose masts a virtual brand leases.
MVNO / virtual operatorA brand upon leased masts — Tesco Mobile upon O2; SMARTY upon Three.
Not-spotA location no usable signal reaches — the object of satellite messaging trials.
OTPA one-time passcode. Disclosed to no caller, under any account, ever.
PACThe code transferring one's number to a new network. Free: text PAC to 65075.
Spend capA self-imposed billing ceiling — free upon every network and chronically neglected.
STACThe code closing a line without retaining the number. Free: text STAC to 75075.
Text-to-SwitchThe Ofcom system underlying the one-text departure.
Wi-Fi CallingCalls across broadband where masts cannot reach — the no-cost remedy for indoor dead spots.

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