Zinc Alloy TM1990 iButton Probe Reader with LED

Products Description:

64 Bit Serial Number iButton/TM1990A-F5 TM Memory Card, TM1990B-F5

Rewritable ibutton TM Card in DS1990A-F5, TM1990B-F5, tm01

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.

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.

TM1990-F5 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.

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.