Reference
Classic phone glossary
The words you meet when you bring a classic phone back into use, explained in a sentence or two.
- Java ME (J2ME)
- The version of Java made for phones and small devices, launched by Sun Microsystems in 1999 as J2ME. Most phones of the 2000s used it to run downloadable apps and games. More.
- MIDP
- Mobile Information Device Profile: the part of Java ME that defines what an app can do (screen, keys, network, storage). MIDP 1.0 (2000) is very limited; MIDP 2.0 (2002) became the standard. KeyAgain’s main app needs MIDP 2.0; a lighter version runs on MIDP 1.0.
- CLDC
- Connected Limited Device Configuration: the core Java underneath MIDP. CLDC 1.0 lacks decimal numbers; CLDC 1.1 adds them. The Nokia 6600 is a well-known CLDC 1.0 phone.
- MIDlet
- The technical name for a Java ME app. KeyAgain on your classic phone is a MIDlet.
- JAR file
- The file that contains a Java ME app (a .jar is a zip archive). KeyAgain’s is about 156 KB.
- JAD file
- A short text file that describes a Java app (name, version, size, download address). Some phones like to open it before the .jar.
- OTA install
- Over-the-air: installing an app straight from the phone’s browser, without a computer. How to install.
- APN
- Access Point Name: the setting that tells the phone which gateway of your operator to use for mobile data. Old phones often need it typed in by hand. Set it up.
- 2G (GSM, GPRS, EDGE)
- The second generation of mobile networks. GPRS and EDGE are its data services, slow by today’s standards but enough for messages. Most classic phones need 2G.
- 3G (UMTS, HSPA)
- The third generation, with faster data. Later classic phones (Nokia E- and N-series, RAZR2 V9, many BlackBerrys) have it, and fall back to 2G when needed.
- 2G/3G switch-off
- Operators closing old networks to reuse the airwaves for 4G and 5G. In much of Europe and North America 3G closed first and 2G remains. By country.
- Nokia Series 40
- Nokia’s system for everyday keypad phones (bar, slider, flip, QWERTY), used on hundreds of models. Most run Java apps. Series 40 phones.
- Nokia Series 30 / 30+
- Nokia’s system for its most basic phones, including the 2017 Nokia 3310. As far as we know, these don’t install Java apps.
- Symbian / S60
- The smartphone system of Nokia’s 2000s phones (6600, N-Gage, E71, N95, 701). S60 was Nokia’s interface on top of it. Symbian runs Java apps alongside native ones. Symbian phones.
- BlackBerry OS
- The system of classic BlackBerrys (Curve, Bold, Pearl) up to version 7.1, built on Java. Not the same as BlackBerry 10, which doesn’t run Java ME apps. BlackBerry phones.
- KaiOS
- A system for newer keypad phones (such as the Nokia 8110 4G and 2720 Flip) that runs web apps, not Java ME. KeyAgain’s app doesn’t run on it.
- phoneME
- An open-source Java ME runtime. Installed on Windows Mobile, it lets devices like the HP iPAQ run Java apps such as KeyAgain.
- Feature phone / classic phone
- A phone with physical keys and a simple system, as most phones were before smartphones. Many could run small Java apps.
- Dumbphone
- An informal name for a simple phone used on purpose, to spend less time on screens. A classic Java phone with KeyAgain is one way to do it while keeping your chats.
- T9
- Predictive text for number keypads: press each key once and the phone guesses the word. Makes typing on a keypad much faster.
- Linked device
- A second device connected to your WhatsApp account, like WhatsApp Web. The smartphone stays the main device and must come online at least every 14 days. KeyAgain uses this route, unofficially (beta).
- TLS / HTTPS
- The encryption that protects connections on the internet. Old phones only know old TLS versions, so KeyAgain’s app brings its own encrypted connection to our server. More.
- End-to-end encryption
- Encryption where only the sender’s and receiver’s devices can read a message. KeyAgain isn’t end-to-end: its server has to read messages to deliver them to a classic phone.
- MVNO
- A mobile brand that rents a bigger operator’s network instead of owning masts. If the host network switches 2G off, the brand loses 2G too.
- Mini-SIM
- The full-size SIM card that classic phones take. Newer SIMs can be fitted with an adapter, but adapters can get stuck in tight slots.
- SIM lock / unlock code
- Many phones were sold locked to one operator. The original operator can provide an unlock code so the phone accepts other SIMs.
- Pairing code
- The 6-digit code KeyAgain shows on the classic phone the first time. You type it once in your account to connect that phone. Never share it.