Phone, SIM and broadband jargon, explained

#

4G

The fourth generation of mobile data, available on every UK network and fast enough for streaming and video calls almost everywhere.

5G

The newest mobile data standard: faster and less congested than 4G where it’s available. You need a 5G phone and a plan that includes 5G. 5G phone deals.

A

Airtime plan

The part of a split contract that pays for calls, texts and data. When the device plan is paid off, only the airtime plan remains.

Annual price rise

A fixed increase to your monthly price, usually every April. Since January 2025 it must be stated in pounds and pence before you sign. Every network’s rise.

B

Bill cap

A limit you set on spending beyond your allowance, such as calls to premium numbers or roaming. Once reached, extras are blocked until the next bill.

Broadband line rental

The charge for the phone line that some broadband services use. Most UK providers now include it in the broadband price.

C

Cashback

Money a retailer pays back after you buy, usually by claim. It lowers the real cost, but only if you remember to claim it on time.

Contract length

The minimum term you agree to pay for: usually 24 months for phones and 1, 12 or 24 months for SIM only.

Credit check

A search of your credit file before a pay monthly contract. Most networks run a hard check, which leaves a mark on your file. Options with bad credit.

D

Device plan

A loan-style agreement that pays off your phone over a set period, separate from your airtime plan. O2 and Sky Mobile sell phones this way.

Dual SIM

A phone that can run two numbers at once, using two physical SIMs, a SIM and an eSIM, or two eSIMs.

E

Early exit fee

What you pay to leave during your minimum term, usually close to the remaining monthly payments. Text INFO to 65075 to see yours.

eSIM

A SIM built into the phone that you download instead of inserting. Which UK networks offer eSIM.

F

Fair use policy

Limits written into “unlimited” plans to stop very heavy or business use — often tethering or roaming caps.

Full fibre (FTTP)

Broadband with fibre running all the way into your home. Faster and more reliable than part-fibre lines.

FTTC

Fibre to the cabinet: fibre to the street cabinet, then copper to your home. Speeds fall the further you live from the cabinet.

I

IMEI

Your phone’s unique 15-digit number. Dial *#06# to see it; networks use it to block lost or stolen phones.

M

MVNO

A mobile network that rents capacity on another network’s masts, such as giffgaff on O2 or SMARTY on Three. Same coverage, often lower prices.

N

Network unlocked

A phone that works on any network. Phones sold in the UK since December 2021 must be sold unlocked.

O

Out of contract

When your minimum term has ended but you’re still paying. You can usually save by switching to SIM only. What to do.

P

PAC code

Porting Authorisation Code: text PAC to 65075 to move your number to a new network. It lasts 30 days. How to switch.

Pay as you go (PAYG)

Top up first, then use. No contract and usually no credit check. PAYG deals.

Porting

Moving your existing number to a new network, done with a PAC code within one working day.

R

Roaming

Using your phone abroad. Several UK networks now charge a daily fee in the EU; some include roaming in the plan.

S

SIM free

A phone bought outright with no contract attached. Pair it with any SIM only plan. Is it cheaper?

SIM only

A plan with no phone included: you keep your own handset and pay only for calls, texts and data. SIM only deals.

Social tariff

Cheaper broadband or mobile plans for people receiving certain benefits, such as Universal Credit. Ask your provider which ones you qualify for.

STAC code

Service Termination Authorisation Code: text STAC to 65075 to leave a network without keeping your number.

T

Tethering

Sharing your phone’s data with another device as a Wi-Fi hotspot. Some plans limit or charge for it.

True total cost

Our figure for what a deal really costs over the contract: upfront cost, every monthly payment and each April rise. How we calculate it.

U

Upfront cost

What you pay on the day for a phone on contract. A higher upfront cost usually lowers the monthly price.

V

VoLTE

Voice over LTE: calls carried over 4G. Needed for calls as UK networks switch off 3G.

W

Wi-Fi Calling

Making and receiving calls over Wi-Fi when mobile signal is weak, at no extra cost on most networks.