They can be identified by wiring, depending on connection type, Wiegand or RS-485.
1. Wiegand Connection:
When connecting Wiegand readers in multiple reader mode the secondary reader that is connected will have all connections wired to the same port as the primary card reader with the DATA 1 connection wired to the opposite reader inputs DATA 1 input.

2. RS-485 Connection:
Entry: Green and orange wires not connected.
Exit: Green and orange wires connected together

Released for: Schneider Electric Saudi Arabia