Technical Glossary -- (Kurt Smith)

CLIP (Calling Line Identification Presentation) is a supplementary GSM service used to show the number of a caller. When a call is initiated, the caller’s MSC provides the destination MSC with the caller’s identity. The destination MSC then checks to see if the phone being called has subscribed to CLIP. If it has, then the caller’s identity is presented. CLIP couples with CLIR to provide an advanced version of caller line identification in GSM networks.

The presence of CLIP - and CLI generally - can be very useful for choosing to forward or even discard calls from certain people or organisations, as it allows identification of the caller without answering.

Also known as: CLIR

CLIR (Calling Line Identification Restriction) controls the presentation of caller identity (via CLIP) in GSM networks. If CLIR is enabled, the caller’s MSC indicates this restriction to the destination MSC. The identity is then not forwarded to the destination mobile station.

There is a GSM override function for the CLIR that is available to organisations such as the police, and allows the caller ID to be seen even if they have elected to restrict their identity.

computer aided manufacturing

Cameraphone (or Camphone) is the name used to describe a device that combines the features of a mobile phone and a digital camera. This means that a cameraphone not only functions as a normal mobile phone, but it is also capable of taking photographs that can then be transferred over-the-air to other phones. Some cameraphones are even able to record live video clips, and most 3G phones are equipped with a camera enabling them to be used for 2-way video calls.

The usual arrangement is that the camera is completely integrated within the phone body, although there are several models where the camera comes as a plug in accessory. As with other digital cameras, a cameraphone is likely to use either a CCD or CMOS sensor (the two main types), which converts the light entering the lens into an electrical signal, and this signal is processed to produce the photograph. The image may then be viewed on the phone’s screen, or it can be stored in the phone’s internal memory for later use.

Cameraphones typically use small lenses with a fixed focus and aperture, and although these lenses give sharp pictures at a distance of between a few feet and infinity, they are not suitable close-ups (with the exception of a couple of phones that have macro settings). In most cases the lens will be located in a fixed position on the phone, but some have a moveable lens that can be rotated by the user.

Most cameraphones provide limited control over the exposure and other normal camera adjustments, but they do usually offer some means for the user to edit the photographs taken. Many models are fitted with a rather weak LED “flash” light, but a few cameraphones are designed to use a more effective plug in flashgun, which is often available only as an accessory. A digital zoom control is provided to magnify parts of the photograph, although this can worsen the picture quality if over magnified, and due to the way digital zoom operates it is usually unavailable at the higher camera resolutions. Cameraphones are now starting to appear with optical zoom and adjustable lenses, which can only enhance their functionality.

Taking lots of pictures will put a strain on the phone’s internal memory, which is of fixed capacity and shared with other phone features. This problem has been overcome in those phones that have a memory card slot, since a full card can be easily replaced with an empty one, and so an unlimited number of pictures can be stored. As memory cards can be read by other devices, this may prove a convenient way to transfer picture files, or for printing. Phones fitted with Bluetooth™, an infrared port or a data cable connector also offer the user the capability to download their pictures onto other devices, such as their home PC.

Apart from taking photographs of other people or scenes, cameraphones also allow a user to take self-portraits. It is sometimes possible for users to view themselves on the phone’s display screen, if not, most cameraphones have a small mirror fitted near their lens, to help aim the shot. A timer is another universally available feature on cameraphones, which allows a delay to be set for a shot.

The growth of MMS messaging means that many users now exchange photographs between compatible MMS phones, although the size of the MMS file is usually restricted to 100 kB. Some network operators also allow the user to transfer pictures to a Web-based album, so that they can be stored online in a virtual photo album, for sharing with friends and other contacts. Alternatively, the pictures may be sent as attachments to an e-mail address, if the phone has an e-mail facility.

The key feature usually quoted for the quality of a cameraphone is its maximum resolution, a figure given as either a number in pixels (e.g. 1.3 megapixels) or a standard format (e.g. VGA, or 640 x 480 pixels). The resolution determines the best picture quality that the camera can capture, and typically a megapixel camera will be needed to produce acceptable results for standard 6 x 4 inch photographic prints.

The Sharp Corporation launched the J-SH04 - the world’s first camera phone - in Japan in November 2000, and this model included a CMOS image sensor offering a resolution of 110,000 pixels. Today, all the major mobile phone manufacturers produce cameraphones, and the latest models are capable of taking photographs of a similar quality to the average standard digital camera.

Carrier Signal (Carrier Frequency) is a continuous signal of a single frequency, which is suitable of being modulated with (or carrying) a second information signal.

This is the normal method of transferring information by wireless systems, and in telecommunications the carrier frequency is usually a radio signal of much higher frequency than that contained in the information signal. Optical fibre communication networks use light as a communications medium, and the carrier will then be a laser-generated light beam.

compact disk

"(Compact Disc Read-Only Memory). Like music CDs, but may contain information in the form of text, graphics, sound and moving video that can be accessed through a computer. A CD-ROM can store as much information as around 450 floppy discs.",

compact disk recordable

compact disk re-writeable

Real time conversations on the Internet, can occur on the world wide web, Internet relay chat (IRC), through instant messaging, on-line commercial servers (eg AOL or CompuServe). Can be accessed through websites. A chat room is an on-line forum where two or more people can engage in chat (Careaga).