Proximity readers use low-frequency 125 kHz cards or tags, while high-frequency smart card readers use 13.56 MHz credentials, such as MIFARE DESFire or EV2 cards. Mobile credential readers communicate with authorized mobile devices through Bluetooth Low Energy (BLE), allowing access through a smartphone instead of a physical card.

Mullion-mount readers have a narrow profile for mounting on door frames or other narrow surfaces, while single-gang readers fit standard single-gang boxes or mounting locations. Keypad readers add PIN-code entry to card, proximity, or mobile credential access, which supports projects that need more than credential presentation alone.

OSDP connectivity supports supervised, bidirectional communication and can simplify wiring in systems that use multi-drop reader configurations. Wiegand connectivity uses a more established reader-to-controller interface, which can support integration with compatible access control panels but may require separate wiring for each reader and provide less device communication.

Review the reader’s specified power input, such as 12 to 24 VAC or VDC, along with its intended environment, including indoor use or weather exposure and any stated enclosure rating. Confirm that the mounting format, such as mullion, single-gang, or keypad style, matches the door frame, wall box, available wiring, and installation space.