How long will the valid distance for the reader? What is the reason will impact reader distance.
Regular card reader reading distance is 4-10 CM, ID card reader with a logger distance and IC card reader with a shorter distance. If you used the key ring, the card reader reading distance is 1-3 CM. Regular card didn’t require reading distance, they think highly of the stability. Access control card reader product is read the card by fullest magnetic energy to increase the stability rather than by magnetic field’s critical zone. If the card reader read the card with a long distance, it isn’t suitable for access control. Two card reader will interfere with each other for short distance.
Card reading method: Close the card naturally to the card reader. It is unwise to read the card fast with the side.
Card reader installed in the metal cover: card reader is a radio frequency product and will absorb the signal with the metal. If the metal cover is too wide, it will impact the card reader can’t read the card or will have a short distance with card reading. In addiction, it will also impact the card reader with a short distance(it will have a short distance with card reading or read the cards at the same time with two close card reader)
Solve method: Do not install it in the metal cover or dig out the metal around the card reader, or raise the card reader 1-2 CM behind the metal cover. The distance must more than 25CM between two card reader.