Memory Cards

Memory cards cannot manage files and have no processing power for data management. All memory cards communicate to readers through synchronous protocols. In all memory cards you read and write to a fixed address on the card. There are three primary types of memory cards: 1). Straight, 2). Protected, and 3). Stored Value. Before designing in these cards into a proposed system the issuer should check to see if the readers and/or terminals support the communication protocols of the chip. Most contactless cards are variants on the protected memory/ segmented memory card idiom.

1) Straight Memory Cards

These cards just store data and have no data processing capabilities. Often made with I2C or serial flash semiconductors, these cards were traditionally the lowest cost per bit for user memory. This has now changed with the larger quantities of processors being built for the GSM market. This has dramatically cut into the advantage of these types of devices. They should be regarded as floppy disks of varying sizes without the lock mechanism. These cards cannot identify themselves to the reader, so your host system has to know what type of card is being inserted into a reader. These cards are easily duplicated and cannot be tracked by on-card identifiers

2) Protected / Segmented Memory Cards These cards have built-in logic to control the access to the memory of the card. Sometimes referred to as Intelligent Memory cards, these devices can be set to write protect some or the entire memory array. Some of these cards can be configured to restrict access to both reading and writing. This is usually done through a password or system key. Segmented memory cards can be divided into logical sections for planned multifunctionality. These cards are not easily duplicated but can possibly be impersonated by hackers. They typically can be tracked by an on-card identifier.