RFID reader in reading how to prevent collision?

1, slot-oriented mechanisms for conflict prevention

RFID reader/writer using this mechanism for conflict prevention, where theslot is actually a serial number. The serial numbers of the range specified bythe reader, and possible scope, 1-2, 1-1, 1-8, 1-16. When two or more Cards asthey enter the RF field, readers sent Cards to the RF field call command,command specifies the range of slots, Cards in this selects a random numberwithin a specified range as your temporary identification number. Then readersstart with 1 station, if a call to a number that happens to have only one cardhas chosen this number, then this card is selected to win. If the call to thenumber did not answer or if there is more than one card of the card answers,continue down station. If all numbers in the range of values are called hasnot selected a card, then the Cards randomly selected a temporaryidentification number until the call out a card so far.

2, a combination of bits and time slots conflict prevention mechanism

RFID reader/writer using this mechanism. Each card has on the one hand a 7-byte globally unique serial number, on the other hand readers in the processof conflict prevention also uses time slot number, but this number is notrandomly selecting Cards, but only part of the serial number of the card.