Some of our customers ask us how to read the 64-bit ID on top of an iButton because they are new in this field and know little about it. For an iButton as below picture, the ID should be read as 7D0000002CFCDCA14. iButton IDs must be read carefully and correctly. The first 2 hexhexadecimal char and the last 2 ones are easy to miss. The reason this process is so complicated because if we allow a direct edit we will not be able to ascertain who held what key during what time.
Normally this job is easily done by focusing you eyes by one minute. But for an iButton withou any text on it(below picturer), you can not tell the 64-bit ID in a glance since there is nothing on the metal cover. Some clients like to use this blank type iButton key because they do not want you get the ID easily unless you have iButton readers to read them by the 1-Wire protocol. To see how this job is done, refer to OneWireViewer and iButton Quick Start Guide.
Please note that these iButton with 64-bit ID is called Read Only iButton(DS1990A-F3/F5) for the iButton manufacturers provide a guaranteed unique ID.
*Note: iButton and 1-Wire are registered trademarks of Maxim.
ALLMAX is an Integrated High-Tech Which Includes Development, Production, Distribute and Trade. We manufacture & supply iButton, Dallas keys, iButton readers and iButton probes. We offer Chinese domestic ones as well as products by Maxim Integrated. Take a visit to our website iButton.cc for more product detail.