Mobile Dictionary

An older mobile generation used for voice and low-speed data. Japanese carriers have retired or scheduled the retirement of their 3G services.

The mature mobile generation that carries most everyday smartphone data and, with VoLTE, voice calls across broad coverage areas.

The mobile generation designed for higher capacity, lower latency and many connected devices, deployed with several frequency bands and network architectures.

A 5G architecture using a 5G core network rather than relying on a 4G core and 4G control connection as non-standalone 5G does.

The step that switches your line onto the new SIM and network. Until activation finishes, the new SIM has no service.

An older broadband technology that sends data over a copper telephone line. Major Japanese consumer ADSL services have ended or are being retired.

A serious status shown in a credit record, such as a payment delay of 61 days or more or three months or more, depending on the applicable definition.

A traditional fixed telephone access line using a local telephone number. The network behind it has been modernized, but existing analogue telephone services and rules still differ from fibre or mobile-based fixed phones.

A small configuration that tells the phone how to reach a network's data. Needed when you set up a SIM-free phone or a low-cost SIM yourself; a carrier-sold phone usually sets it automatically.

KDDI's construction-free fixed telephone product that uses a dedicated adapter and the mobile network at the registered location.

A direct-to-phone satellite service for compatible au smartphones outside ordinary au 5G/4G coverage, subject to device, software, location and supported-feature conditions.

A document written or signed by the contract holder authorizing a named proxy to perform specified procedures.

An add-on for cheaper or unlimited voice calls, since many base plans charge per minute.

A time-limited promotion — a device discount, cashback, or points — almost always with conditions attached.

A charge that may apply when a newly opened line is cancelled within a defined period (often 12 months). Rules differ by plan and contract start date; device installments, options and same-month cancellation charges are separate.

Two offers that cannot be used together. You get one or the other.

A company that owns and runs a mobile network. In Japan: NTT DOCOMO, au (KDDI), SoftBank and Rakuten Mobile.

An email address given by a mobile carrier, such as @docomo.ne.jp, @au.com / @ezweb.ne.jp or @softbank.ne.jp.

Internet delivered by a cable television operator, using coaxial cable, a fibre-coax hybrid network or fibre, often bundled with television and fixed telephone service.

Text-based help through a website widget or a messaging app. The main support channel for many online-focused plans.

Credit information held by CIC, a designated credit information agency used by credit companies and participating mobile phone companies.

Written consent from a parent, legal representative, payer or another affected person when the contract or procedure requires their approval.

Video, music and other subscriptions you can attach to your mobile contract so they appear on one bill — sometimes free or discounted for a limited period.

A broad term for changing the details of an existing contract — plan, options, name, or payment method.

A one-time fee the carrier charges for a procedure — new contract, MNP, and sometimes a plan or SIM change.

Where a network provides service. Check it for your home, workplace and commute before you commit.

Selecting the physical card artwork or colour offered for a particular card product, sometimes with restrictions on network brand, grade or family cards.

The payment network shown on a card, such as Visa, Mastercard, JCB or American Express; it is different from the company that issues and bills the card.

How much high-speed data your plan includes each month. After the limit, speeds are reduced.

A separate credit assessment for paying for a phone in installments. Passing the mobile-line screening does not guarantee that the device installment will be approved.

The cost of the phone itself, separate from your monthly service charge.

Getting a new device while staying with your carrier and keeping your number.

Loss or severe degradation of mobile service caused by damaged equipment, power or transmission links, or by unusually concentrated calling and data traffic after a disaster.

DOCOMO's fixed-phone service that connects an ordinary telephone to an HP01 adapter and uses the DOCOMO mobile network without line construction.

Verifying your identity through your phone camera — photographing your ID and sometimes your face — instead of showing documents at a counter.

Making electricity usable again at a supply point that was stopped, normally as part of a new move-in contract.

Changing the electricity retailer for an already powered home without stopping the physical electricity supply.

The specific phone models a campaign applies to. Discounts often do not apply to the model you actually want.

A SIM built into the phone that you activate by scanning a code or through an app — nothing physical is shipped.

A credit check that uses information outside the carrier's own billing records, such as information held by a designated credit information agency.

A registered group of eligible family lines used for discounts, free group calls or shared benefits; it is not always the same as a single household or a combined bill.

A very small indoor cellular base station that uses a compatible broadband connection as its link back to the carrier network.

Changing from FLET'S Hikari to an NTT East/West wholesale fibre collaboration service while normally continuing to use the same access line.

A coordinated switch between eligible NTT wholesale fibre and shared-access fibre services that reuses the existing drop cable instead of installing a second one.

Changing from one NTT wholesale fibre collaboration provider to another while normally reusing the same fibre access line.

A telephone service associated with a home or business location, delivered over analogue copper, fibre/IP, CATV or a mobile-network adapter.

Documents that prove who you are and where you live. For residents this is usually the residence card, sometimes with a supporting document.

A credit agreement in which a finance provider pays the seller for a specific phone purchase and the customer repays the provider in installments.

Paying for a device in monthly amounts (commonly 24 or 36) instead of all at once. A credit check may apply.

The company that connects an access line to the internet and may provide IPv6, authentication, email, security and support services.

Paying the full device price in one payment.

Moving to a different carrier while keeping the same phone number. In shops and advertisements this is commonly called norikae (乗り換え), meaning switching carrier.

A campaign only for customers switching in from another carrier via MNP. New contracts and upgrades do not qualify.

A temporary number from your current carrier that authorises the transfer. It expires after a set number of days.

A fee that used to be charged for leaving or joining a carrier by MNP. Many carriers now charge nothing, but check both sides.

A vehicle carrying cellular base-station and antenna equipment that temporarily supplies or adds coverage where permanent equipment is unavailable or overloaded.

The wireless signal between a phone and a base station. Coverage, frequency, building materials, terrain, congestion and the device all affect the connection.

Carrier-managed equipment that receives an available outdoor mobile signal and repeats it indoors to improve coverage in part of a building.

The recurring charge for your mobile service — data, calls and any options.

A company that sells mobile service using capacity rented from a carrier. Cheap, but peak-time speeds and support vary.

A carrier's power to block a specific handset from its network by IMEI — used mainly when a device bought on instalments is not being paid for, or is reported lost or stolen. A used phone is commonly graded ○ (clear), △ (instalments still being paid) or × (restricted / blocked).

Signing up for a new line. You usually receive a new phone number.

Starting electricity supply for a location where you are not simply switching the retailer of an already active contract.

Starting a fibre service where no transferable contract route is used. An area check, building check and possibly construction are required.

A campaign price available only through the website — not at shops.

A plan where application, account management and support happen mainly or entirely online.

A step you complete yourself on a website or app — sign-up, plan change, MNP, or SIM activation.

Assistance that costs a service fee — often for setup, data transfer, or guiding you through an online application.

A telephone help line. Some online-focused plans do not offer this as a standard channel.

Changing your pricing plan while staying with the same carrier or brand group. Not the same as MNP.

A discount paid as loyalty points rather than money off the price. Check where the points can be spent and when they expire.

A person who visits or applies on behalf of the contract holder within the carrier's permitted procedures and relationship rules.

Use of a legally recorded common name instead of, or together with, the legal name on a contract. Acceptance differs by carrier and application channel.

Building internet arranged by the landlord or manager and included in the rent or common-area charge rather than contracted separately by each resident.

A paid add-on that a particular campaign may require. The minimum-use period and cancellation timing must be checked in that campaign's terms.

The card issued to mid- and long-term residents of Japan. The main ID for a mobile contract. Must be valid, not expired.

You do the procedure yourself, without staff doing it for you.

An extra upfront amount some shops add on top of the device price. It is set by the shop, not the carrier, and is not a deposit toward anything.

The small chip that connects your phone to a mobile network. Comes in a physical form you insert.

A restriction that ties a phone to one carrier. New phones sold in Japan are now generally sold without it, but older devices may still be locked.

A phone with no SIM lock, which can be used with any compatible carrier's SIM.

A short lesson, usually free and run by a carrier or a local government, that teaches smartphone basics — calls and messaging, camera, maps, cashless payment, video calls, security and scam awareness.

SoftBank's construction-free fixed telephone service that connects a telephone to a dedicated unit and uses the LTE network.

A campaign price available only in shops — not online.

Booking a time slot before visiting a carrier shop.

Help you can get by visiting a physical shop. Its meaning ranges from 'staff do everything' to 'paid help while you do it yourself'.

A cheaper brand run by a carrier, usually with its own shops and support — for example UQ mobile or Y!mobile.

The character set, spacing and maximum length accepted by a carrier's application system. There is no single limit shared by every carrier and channel.

A small number-based charge that supports the 24-hour telephone relay service used by people who are deaf, hard of hearing or have speech difficulties.

A small charge linked to each eligible telephone number that helps maintain nationwide basic telephone services, public telephones and emergency-call access.

A building arrangement where fibre reaches a shared equipment room and existing copper telephone wiring carries the connection to each apartment.

A paid in-store service where staff help you complete an online sign-up that you operate yourself.

A paid in-store service where staff help you carry out an online change (for example a plan change or MNP) that you operate yourself.