Compatible DALLAS iButton Cards

Touch Memory Cards(TM Cards)  (commonly known as Pengpeng card or Button card, also known as iB card (iB is the abbreviation for iButton)) is a patented product of DALLAS Inc., U.S., which communicates with the reader through single line protocol and data read-writes are completed through an instant touch. The card is not only provided with operability of Contactless IC card, but also possesses low cost of Contact IC card, and is one of the best IC cards that has a fairly high cost performance.

1. The basic principles of TM cards:

 A TM card is similar to a button battery in shape and can be inlaid into a card, key button and other objects.

You can replace the data line, address line, control line and power line with a single line so that TM card achieves single line communication through a multi-function device. When the host is powered, TM card gives the response to the host through switching the impedances between 50Ω and 500,000Ω. The lengths of time the signal is pulled down(long or short) show the digital logics(long=1, short=0). Due to the range of witching impedances is 1-10,000, the resistances of the contact points will not affect the identification of the digital signals.

2. Some types of TM cards:

         Type                       Description                                                           Scratchpad

       DS1982                     Only add Memory                                                              1024 bits

       DS1990A F3/F5        Touch-type Serial Number

       DS1991L F5             Multiple Touch-type Keys 3 encrypted District              512 bits

       DS1992L F5             Touch-type Memory                                                           256 bits

       DS1993L F5             Touch-type Memory                                                           256 bits

       DS1994L F5             Touch-type Memory with a clock                                     256 bits

       DS1995L F5             Touch-type Memory                                                           256 bits

       DS1996L F5             Touch-type Memory                                                           256 bits

       DS1991 TM card is mostly compatible with DS1425 TM cards.

       DS1990 TM card is mostly compatible with DS1990A TM cards.

3. According to whether the Memory in TM card is encrypted or not, TM card can be divided into encrypted TM card and non-encrypted TM card.

 Most of TM cards are non-encrypted.

 DS1991 card is an encrypted card which is divided into three separate encrypted sectors. Each encrypted sector has its own password and the three sectors can be respectively used for three separate purposes. DS1982 card is programmable.

TM card’s encrypted method is different from Contactless IC Encrypted cards: The former has 64-bit password without the function of error calculation, while the latter has shorter password and the function of error calculation. If you forget your password by chance, you can reuse your TM card after re-initializing it, but the information in your card will be automatically rewritten.