STORED MEMORY CARDS A WORLD VIEW

By Peter Granfield

Since the inception of phonecard systems, many different companies have developed their own systems and some countries have chosen to go their own way rather than use existing developments and create another system unique to their own country Anritsu card used in Australia There are three main variants in use are: magnetic, optical, and smart card (All figures are end of the page - Fig. 1).

MAGNETIC

This has been the system with the greatest number of variants. The basic principle being that the information is stored on the card in the form of a magnetic field, the place of storage being unseen on some such as the Anritsu system used in Australia and the Tamura system used in Japan Magnetic systems are prone to corruption of the data by another magnetic field such as a credit card. If stored in a wallet or purse against a credit card, which has a stronger magnetic field, the credit on the phone card can be wiped (Fig. 2).

TAMURA CARD

An advantage of of these two systems is the very thin card used and production costs of around l5c per card. Cases of fraud involving the sophisticated reprogramming of magnetic cards has occurred in more than one country. The Anritsu and Tamura cards both give an indication of the approximate remaining credit to the user by means of a punched hole. On the Anritsu system the indicator scale is a standard length regardless of the value of the card. So on a $2.00 card a hole will be punched for every 30c call made, ie., a maximum of 7 holes. However, on a $20.00 card ($21.00 credit) there is insufficient room to punch a possible 70 holes so the card only gets punched a maximum of 11 times as the remaining credit value decreases. There goes the theory that it was a free call because it didn't punch the card. On the Tamura cards the use indicator is longer on a card with a greater number of units, although this appears to be a logarithmic extension. The much flouted theory that blocking the punched holes allows the reuse, or extension of credit, is total nonsense because the card reader is reading magnetic information, not holes. The holes are merely punched as a consumer friendly gesture. With Autelca system by a Swiss company, the the information is stored on the visible magnetic strip like the Hong Kong card on the right. In this card it is necessary to insert the card in a phone to determine any remaining credit (Fig. 3).

The card on the Fig. 4 from Eastern Telecom Philippines comes from GPT of the United Kingdom. It has a use indicator which has a dent punched in the card as it is used, whereas others, like the New Zealand card, has no use indicator and again it is necessary to insert the card into a phone to determine the credit.

The card on the Fig. 5 is from Italy and uses what is commonly referred to as an Urmet system, but can be made by at least 3 different companies. Before using these cards, you are required to tear of the perforated corner. Unless this is done, the card will not be able to be inserted far enough into the phone to allow operation. These cards, as with a few others, have an expiry date after which the card becomes invalid.

SMART CARD

This is the system with the second greatest number of variants. The storage of these cards is done on a processor chip which is built into the card. The greatest part of what is visible is the contacts which connect to the chip. It is necessary to insert the card into a phone to determine if there is any credit remaining on the card. Mint cards usually come in a sealed pack as proof of being unused. Smart cards have the added advantage of being far more flexible in what they can be used for. The memory capacity is such that they can be used for funds transfer and many other uses. Denmark have just successfully trialed a system which uses the one card for phone, laundry, parking, snack and newspaper machines. There is now a standard chip location (Fig. 6).

OPTICAL

This system, which to my knowledge is unique to Landis & Gyr of Switzerland, uses an optically encoded information strip which is embossed into the plastic phonecard. The card reader verifies the information and burns part of the strip as the credit is used up. Optical cards are free of environmental influences such as magnetic fields and high humidity which makes them ideal for tropical countries. It is necessary to insert the card into a phone to determine if there is any credit remaining on the card. Mint cards usually come in a sealed pack as proof of being unused. There have been no recorded cases of fraud where this system is in use. The information strip is usually white allowing easy identification of the value left on the card. However in some cases the strip is the same colour as the remaining card design and it is then necessary to catch the light on the card to see what appears as tracking on the strip area. The more units available, the longer the use indicator. In some cases such as the Thailand 200 unit cards (left), there are actually 2 strips on the card, one near the top and one near the bottom, each bearing 100 units. These cards are turned upside down to access units 101 to 200 (Fig. 7 - 8).