Editing Telephone card (section)

==Stored-value phone cards==

A stored-value phone card stores the available credit balance in an analog or digital memory physically embedded in the card. This balance can be read by a public [[payphone]] when the card is inserted into the card reader. This is superficially similar to a bank [[automated teller machine]], but a stored-value card is more closely analogous to a change purse. While ATMs (as well as the remote memory systems discussed below) use the card merely to identify the associated account and record changes in a central database, stored-value systems make a physical alteration to the card, or write data to an embedded chip or magnetic stripe to reflect the new balance after a call. Some magnetic cards also show the remaining value.

Used primarily for payphones, stored-value systems avoid the time lag and expense of communication with a central database, which would have been technically complex before the 1990s. 

There are several ways in which the value can be encoded on the card:

The earliest system used a [[magnetic stripe]] as information carrier, similar to the technology of ATMs and key cards, and the first magnetic strip phonecard, manufactured by SIDA, was issued in 1976 in [[Italy]].

[[File:TWK (1).jpg|thumb|right|Optical phonecards from Austria. The balance is shown by the vertical marks on the white bar.]]
The next technology used optical storage. Optical phonecards get their name from optical structure embossed inside the cards. This optical structure is heated and destroyed after use of the units. Visible marks are left on the top of the cards, so that the user can see the balance of remaining units. Optical cards were produced by [[Landis+Gyr]] and Sodeco from Switzerland and were popular early phonecards in many countries with first optical phonecards successfully introduced in 1977 in [[Belgium]]. Such technology was very secure and not easily hackable but chip cards phased out the optical phone cards around the world and the last [[Landis+Gyr]] factory closed in May 2006 when optical phonecards were still in use in few countries like [[Austria]], [[Israel]] and [[Egypt]].

The third system of stored-value phone cards are [[smart card|smart cards]] and use an embedded microchip. These were first launched on a large scale in 1986 in [[Germany]] by [[Deutsche Bundespost]] after three years of testing, and in [[France]] by [[Orange S.A.|France Télécom]]. Many other countries followed suit, including Ireland in 1990 and the [[United Kingdom|UK]] circa 1994–1995, which phased out the old green Landis+Gyr cards in favor of the chip (smart) cards. The initial microchips were easy to hack, typically by scratching off the programming-voltage contact on the card, which rendered the phone unable to reduce the card's value after a call.  But by the mid-to-late 1990s, highly secure technology aided the spread of chip phonecards worldwide.