School canteens punch card machine is what principle?

Answers:1   |   LastUpdateAt:2012-04-03 04:16:31  

Asked at 2012-04-03 04:14:34
School canteens machine punch card is what principle ?
Answer1liquid ice Answered at 2012-04-03 04:16:31
Primarily known for radio frequency technology radio frequency identification , RFID is a technology of radio frequency identification in English ( RadioFrequencyIdentification ) acronym is a radio frequency identification technology using radio frequency signals through space coupling (magnetic field or alternating electromagnetic field) to achieve non- contact transmission of information transmitted through information technology to achieve identification purposes. With the current widespread use of automatic identification technology such as cameras , bar codes , magnetic cards, IC cards, compared with the RFID technology has many unique advantages: first, non-contact operation , identification of long-range (a few centimeters to tens of meters) , so that recognition of the work done without human intervention, application installations , secondly , no mechanical wear , long life, and work in a variety of grease, dust , pollution and other harsh environments , third , high speed of moving objects can be identified and may also identify a number of electronic tags ; Fourth, the reader does not open directly to end users physical interface to ensure their own safety , fifth, that the data security password protected electronic tag , the data part of a series of algorithms available to implement safety management , the Sixth , between the reader and make the process of mutual authentication , communications safe and storage.
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