HD500-EM Heavy Duty Prox Reader. The HD500-EM reads EM4102 cards (also known as Miro or UNIQUE 125 kHz). Vandal-proof and fire-resistant, it is popular both in vulnerable locations and modern office environments. When BC-Link is used two of these readers can be installed to control entries and exits using only one door controller. An additional benefit of BC-Link is that it supports online status monitoring. Card technology: EM4102 (also known as Miro or UNIQUE 125 KHz), Card compatibility: IB41-EM, IB42-EM, IB44-EM, IB45-EM, Card read distance: Up to 6 cm.