First, check the output breakers on the back plate of the UPS. If an attached device draws too much current the output breaker for that outlet(s) will trip as a safety measure. The breakers on the back of the unit are generally of the pop-up variety, and will stick out approximately 1/2"" when tripped. Press the breaker plunger to reset. Please note that pressing in on an un-tripped breaker may cause a momentary loss of output power.
If all breakers are un-tripped and your UPS features a user replaceable backplate, verify that there are no loose or disconnected wires on the backplate. For a tutorial on how to remove and replace the backplate on a Smart-UPS, please refer to FA156589.
SMT, SMX, and SRT Series:
SMT, SMX, and SRT series Smart-UPS support switchable outlet groups that can be controlled via software or via the front panel LCD. In addition to checking the output circuit breakers, you would want to ensure that the outlet group(s) is turned on. From the ""Control"" menu on the UPS, you would scroll to each outlet group and choose ""TurnON - No Delay"". This will restore power to the outlets in that group. If the outlets are already ON, ""TurnON - No Delay"" will not be an option in the menu.
For additional information on the functionality of switched outlet groups on SMT/SMX units, please review APC Application Note #177 "Software Interface for Switched Outlets and UPS Management in Smart-UPS"