The Altronix Model SMP3 power supply/charger converts low voltage AC input, to a 6VDC, 12VDC or 24VDC @ 2.5 amp of continuous supply current output. Model DPS3 is a DIN Rail Mount version of this product. SMP3 is a power supply/charger that converts a 16-28VAC input to a 6, 12, or 24VDC output. This power supply/charger is typically used in access control, security, and CCTV systems. Its compact design and snap track compatibility make installation quick and painless. The built-in charger keeps the backup battery charged to full capacity. In situations where power is interrupted, the SMP3 automatically switches over to backup battery power. Also known as -SMP3 Proprietary Power Supply