Japan cell phone gossary
What is Unlocked Cell Phone?
What is Dual-band/Tri-band/Quad-band
What is GSM?
What is WCDMA?
What is CDMA?
What is 3G?
What is a SIM Card?
What is Pre-Paid Phone Cards?
What is SMS?
What is EMS?
What is MMS?
What is PHS?

Japan is in the midst of significant changes in these areas. This is an introductory guide that introduced by MyJapanphone with information about CDMA, EMMS, Unlocked Cell Phone and more. Hope it can help you to learn more about Japan Cell Phone.

Some cell phones are designed to use a Subscriber Identification Module (SIM) card, or microchip that stores subscriber data. The SIM card is issued by a carrier and provides cell service by activating any phone into which it is inserted. A locked phone, however, will only recognize a SIM card from a particular carrier. If the cell phone is unlocked, it will recognize a SIM card from any carrier. The "lock" is software setting that keeps the cell phone "loyal" to one carrier.

In areas like the United States where carriers offer free or deeply discounted phones with cell plans, the phones are commonly locked so that they will not work with other carriers. Carriers claim this is necessary to subsidize the cost of the phones.

After a period of time, a carrier might agree to unlock the phone upon request, perhaps charging a fee. However, due to proprietary settings sometimes installed in locked handsets, the phones don't always function correctly with other carriers, even once unlocked. From the viewpoint of the consumer, the practice of carriers locking phones and using proprietary settings defeats many of the benefits of SIM handsets. Complaints led to a class action suit filed in California in June 2004 by American watchdog group Foundation for Taxpayer and Consumer Rights (FTCR). Ideally phones should be left unlocked or at least unlocked after the initial contract expires.

The downside is that the price is commonly close to full retail. Some consumers might find it tough to dish out big bucks for a phone that they can get for free with a plan. The advantage is that the third party unlocked phone should work equally well with any carrier that uses SIM cards.
Unlocked cell phones are in such demand that third party services will unlock your cell phone for a fee. This doesn't guarantee the phone will always work correctly, as proprietary settings might remain. There are also hacking instructions online to unlock many models of phones, but a phone that is unlocked improperly can be rendered inoperable.

Carriers operating on the GSM network use SIM cards. In the United Sates, this includes Cingular Wireless, now one with AT&T Wireless, and T-Mobile. Carriers that use the competing CDMA network do not yet use card-enabled phones. These carriers include Sprint PCS, Verizon and Virgin Mobile. The CDMA equivalent of the SIM card - the R-UIM - will be used by these carriers in the future. R-UIM cards are already in use in some parts of Asia.

Dual-band - A dual-band phone operates at both the 900 MHz and 1800 MHz spectrum. Dual-band works in Europe, Africa, Asia, Australia, New Zealand and much of South America.

Tri-band - A tri-band phone operates on three frequency bands, 900 MHz, 1800 MHz and 1900 MHz, allowing you to use it in Europe, Africa, Asia, nearly all of North America, Australia and New Zealand

Quad-band - A quad-band phone allows you to roam almost anywhere globally. It covers the 850 Mhz, 900 MHz, 1800 MHz and 1900 MHz frequency ranges. Many countries in South America only have 850 MHz GSM service while both 1900 MHZ and 850 MHz GSM services are supported in the USA. 99% of all countries use the GSM standard. WE believe eventually GSM will be the only cell phone standard in the world.

GSM (Global System for Mobile Communications) leads the world as the fastest growing, most reliable and advanced digital technology available in the marketplace today. GSM provides integrated voice mail, high-speed data, fax, paging and short message services capabilities. GSM customers enjoy secure communications, and GSM offers unparalleled call privacy and fraud prevention. As members of the GSM Global Network, GSM subscribers can use their phones at home, across town, across the continent, or around the world (except for with country specific SIM cards). GSM operates on the multiple spectrum frequency bands used around the world - 1900MHZ, which is used in North America and 900MHz and 1800 MHz for other locations. Different mobile phone networks operate at different frequencies, which mean that if you wish to use your mobile phone outside your home country, you generally need a handset that supports multiple frequency bands. Make sure that the cellular phone you are interested in is compatible with the GSM band of the country you will use it in. GSM was first introduced in 1991. As of the end of 1997, GSM service was available in more than 100 countries and has become the de facto standard in Europe and Asia.

Short for wide-band CDMA (Code-Division Multiple Access), a 3G technology that increases data transmission rates in GSM systems by using the CDMA air interface instead of TDMA. WCDMA is based on CDMA and is the technology used in UMTS. WCDMA was adopted as a standard by the ITU under the name "IMT-2000 direct spread".

Short for Code-Division Multiple Access, a digital cellular technology that uses spread-spectrum techniques. Unlike competing systems, such as GSM, that use TDMA, CDMA does not assign a specific frequency to each user. Instead, every channel uses the full available spectrum. Individual conversations are encoded with a pseudo-random digital sequence. CDMA consistently provides better capacity for voice and data communications than other commercial mobile technologies, allowing more subscribers to connect at any given time, and it is the common platform on which 3G technologies are built.

CDMA is a military technology first used during World War II by English allies to foil German attempts at jamming transmissions. The allies decided to transmit over several frequencies, instead of one, making it difficult for the Germans to pick up the complete signal. Because Qualcomm created communications chips for CDMA technology, it was privy to the classified information. Once the information became public, Qualcomm claimed patents on the technology and became the first to commercialize it.

3G is an ITU specification for the third generation (analog cellular was the first generation, digital PCS the second) of mobile communications technology. 3G promises increased bandwidth, up to 384 Kbps when a device is stationary or moving at pedestrian speed, 128 Kbps in a car, and 2 Mbps in fixed applications. 3G will work over wireless air interfaces such as GSM, TDMA, and CDMA. The new EDGE air interface has been developed specifically to meet the bandwidth needs of 3G.

A SIM card or Subscriber Identity Module is a portable memory chip used in some models of cellular telephones. The SIM card makes it easy to switch to a new phone by simply sliding the SIM out of the old phone and into the new one. The SIM holds personal identity information, cell phone number, phone book, text messages and other data. It can be thought of as a mini hard disk that automatically activates the phone into which it is inserted.

A SIM card can come in very handy. For example, let's say your phone runs out of battery power at a friend's house. Assuming you both have SIM-based phones, you can remove the SIM card from your phone and slide it into your friend's phone to make your call.
Your carrier processes the call as if it were made from your phone, so it won't count against your friend's minutes.

If you upgrade your phone there's no hassle involved. The SIM card is all you need. Just slide it into the new phone and you're good to go. You can even keep multiple phones for different purposes. An inexpensive phone in the glove compartment, for example, for emergency use, one phone for work and another for home. Just slide your SIM card into whatever phone you wish to use.

High-end cell phones can be very attractive and somewhat pricey. If you invest in an expensive phone you might want to keep it awhile. Using a SIM card, it is even possible to switch carriers and continue to use the same phone. The new carrier will simply issue you their own SIM card. The phone must be unlocked, however, and operate on the new carrier's frequency or band.

A SIM card provides an even bigger advantage for international travelers -- simply take your phone with you and buy a local SIM card with minutes. For example, a traveler from the U.S. staying in the U.K. can purchase a SIM card across the pond. Now the phone can be used to call throughout England without paying international roaming charges from the carrier back home.

SIM cards are used with carriers that operate on the Global System for Mobile Communication (GSM) network. The competing network is Code Division Multiple Access (CDMA), a technology created by U.S. Company Qualcomm. As of fall 2005, CDMA cell phones and CDMA carriers do not support SIM cards in most parts of the world, though this is changing. A CDMA SIM card called the R-UIM (Re-Useable Identification Module) was made available in China in 2002, and will eventually be available worldwide. Expectations for the future include a cell phone market that supports both SIM (GSM) and R-UIM (CDMA) cards by default.

A pre-paid phone card is a card you purchase to make long distance phone calls. Many people use a pre-paid phone card because of the cards convenience - it can be used anywhere and, because you pay in advance, there is no bill. Pre-paid phone cards are popular among travelers, students, people who frequently call overseas, and those who haven’t selected a preferred long distance telephone company. In addition, pre-paid phone cards are sold in convenient places, such as newsstands, post offices, and stores. What are Unlocked Cell Phones?

Short for Systems Management Server, a set of tools from Microsoft that assists in managing PCs connected to a local-area network (LAN). SMS enables a network administrator to create an inventory of all the hardware and software on the network and to store it in an SMS database. Using this database, SMS can then perform software distribution and installation over the LAN. SMS also enables a network administrator to perform diagnostic tests on PCs attached to the LAN.
SMS runs under Windows NT but can manage PCs running DOS, all varieties of Windows, and OS/2, as well as Macintosh clients.
Short for Short Message Service Similar to paging, SMS is a service for sending short text messages to mobile phones.

Also known as EMS (Expanded Memory Specification), expanded memory is a technique for utilizing more than 1MB of main memory in DOS -based computers. The limit of 1MB is built into the DOS operating system. The upper 384K is reserved for special purposes, leaving just 640K of conventional memory for programs.

There are several versions of EMS. The original versions, called EMS 3.0 and 3.2, enable programs to use an additional 8MB of memory, but for data only. An improved version developed by AST, Quadram and Ashton-Tate is known as EEMS (Extended EMS).

EEMS enables programs to use extra memory for code as well as for data. The most recent version of EMS (created in 1987) is known as EMS 4.0 or LIM 4.0, LIM being the initials of the three companies that developed the specification: Lotus, Intel, and Microsoft. EMS 4.0 raises the available amount of memory to 32MB.

Until the release of Microsoft Windows 3.0 in 1990, expanded memory was the preferred way to add memory to a PC. The alternative method, called extended memory, was less flexible and could be used only by special programs such as RAM disks. Windows 3.0 and all later versions of Windows, however, contain an extended memory manager that enables programs to use extended memory without interfering with one another. In addition, Windows can simulate expanded memory for those programs that need it (by using the EMM386.EXE driver).

Abbreviated as EMS, an application-level extension to SMS for cellular phones available on GSM, TDMA and CDMA networks. An EMS-enabled mobile phone can send and receive messages that have special text formatting (such as bold or italic), animations, pictures, icons, sound effects and special ring tones.

EMS messages that are sent to devices that do not support it will be displayed as SMS transmissions.

EMS, also referred to as Enhanced Messaging Service, is cross-industry collaboration between Ericsson, Motorola, Siemens and Alcatel, among others.
Also see SMS and MMS.

Short for Multimedia Message Service.
Abbreviated as MMS, Multimedia Message Service is a store-and-forward method of transmitting graphics, video clips, sound files and short text messages over wireless networks using the WAP protocol. Carriers deploy special servers, dubbed MMS Centers (MMSCs) to implement the offerings on their systems. MMS also supports e-mail addressing, so the device can send e-mails directly to an e-mail address. The most common use of MMS is for communication between mobile phones.

PHS (Personal Handyphone System) is a low-powered wireless phone technology developed in Japan and rather different from other cellular phone technologies.

· Designed as dual-mode phone between public wireless network and home (or corporate) phone line.
· Data communication in 32k/64kbps circuit switching or 32k/128k/256kbps packet exchange.
· Can be used even in subway stations or underground arcades because cell stations are relatively small and can be installed easily.

PHS has been deployed in Japan since mid-1990's; now also in China, Taiwan, Thailand (where called PCT) etc. Today PHS is considered as low-cost data communication service rather than voice phone in Japan. Unlimited data communication plans are available