Phone cards, Mobiles and ringtones
Phone Cards
A telephone card, calling card or phone card for short, is a small card, usually resembling a credit card, used to pay for telephone services. Such cards can either employ a prepaid credit system or a credit-card-style system of credit. The exact system for payment, and the way in which the card is used to place a telephone call, depend on the overall telecommunication system. Currently, the most common types of telephone cards involve pre-paid credit (stored-value) in which the card is purchased with a specific balance, from which the cost of calls made is deducted. Pre-paid phone cards are disposable. When the balance is exhausted you simply buy a new card. In some countries, cards purchased can be refilled. The other main type of card involves a card with a special PIN printed on it that allows one to charge calls to a land-line telephone account. These are known as remote memory cards. Cell phones have almost made the use of these cards unneccessary.
Mobile phones - A mobile phone (also called mobile, cellular phone, cell phone or handphone) is an electronic device used for full duplex two-way radio telecommunications over a cellular network of base stations known as cell sites. Mobile phones differ from cordless telephones, which only offer telephone service within limited range through a single base station attached to a fixed land line, for example within a home or an office. Low-end mobile phones are often referred to as feature phones, whereas high-end mobile phones that offer more advanced computing ability are referred to as smartphones.
A mobile phone allows its user to make and receive telephone calls to and from the public telephone network which includes other mobiles and fixed line phones across the world. It does this by connecting to a cellular network owned by a mobile network operator. A key feature of the cellular network is that it enables seamless telephone calls even when the user is moving around. ringtones - A ringtone or ring tone is the sound made by a telephone to indicate an incoming call or text message. Not literally a tone, the term is most often used today to refer to customizable sounds used on mobile phones.
A phone “rings” when its network indicates an incoming call and the phone thus alerts the user. For landline telephones, the call signal can be an electric current generated by the switch to which the telephone is connected. For mobile phones, the network sends the phone a message indicating an incoming call.
A telephone “ring” is the sound generated when there is an incoming telephone call. The term originated from the fact that early telephones had a ringing mechanism consisting of a bell and an electromagnetically-driven hammer, producing a ringing sound. The aforementioned electrical signal powered the electromagnet which would rapidly move and release the hammer, striking the bell. This "magneto" bell system is still in widespread use.