ACM · ACM-TM1990A-F5
Description The TM1990A-F5 electronic iButton key with unique 64-bit code is a full quality analog of Dallas/MaximDS1990A-F5 iButtons. Designed for access control systems each key has a unique family code that is recorded while the key is being produced and the code cannot be overwritten. While manufacturing such devices in the factory, the number is directly assigned directly to theproduction line. Each TM1990A-F5 is assigned a unique identification code consisting of numbers andletters. The approximate number of combinations – 4 billion. Therefore the chance to guess the key fromthe entrance is practically zero. The key contains a number. It can not be charged or magnetized. But it can be stored in the memory controller, which controls the door to the entrance or office. When you touch the ibutton reader with a TM1990A-F5 key, it reads this code and passes it to thecontroller, which checks with the internal memory for its presence in the database. If the identifier with thecode is found, the access rights are checked (in some systems there may be time constraints) and givethe actua