Use the 505EIR when controlling access to a single door.
If you have multiple doors to control, look at Lockenetics models 510 and 515.
These days, there are all types of Input Devices and Output Devices available.
Example input devices: Keypad, Card Swipe, Prox Reader.
Example output devices: Mag Lock, Electric Strike, Electrified Lock.
The 505EIR can handle all types of devices by use of dip switches included with the unit.
During installation, set the dip switches to send either continous our intermittent power to each of the devices.
Use of the EIR module is optional, but it is now included with every 505.
EIR stands for Emergency Interface Relay and is just a fancy name for Fire Alarm Module.
If you have a fire alarm system, wire the system into the EIR Module. It will unlock the door if the alarm should sound.
The idea is to allow access to emergency personnel if the fire alarm sounds.