>Also, the box is on a UPS, so I'm assuming the AC power is generated >from the battery and is a perfect sine wave. But that begs the >question: does a UPS system connect the mains to the output, or is the >input power used to charge the battery, and the battery used to generate >the output power?
Depends. A decent UPS is an "online" UPS meaning that the battery is powering the output all the time. Catch is, online UPS'es are heat factories and eat power because of AC->DC->AC conversion. Anything over 500VA that's reasonably new should be an "online" UPS. They are better because there is no fluctuation in the output in the event of a power failure, brown out, etc. The other kind is a "back" UPS with a switch that is essentially held open by the presence of AC power. When the power fails, the switch is closed, turning on the battery source. There is a lag, however small, between the power failing and the battery kicking in. This messes up the sine wave and causes problems in the case of a PC or a server. This is exacerbated by power fluctuations such as undervoltage as the switch flip-flops back and forth between battery and mains. I have observed this behavior with older APC and *shudder* Tripp-Lite. Cheap Costco retail style UPS'es have this. If it says "back" anywhere on the UPS, get rid of it. _______________________________________________ Asterisk-Users mailing list [EMAIL PROTECTED] http://lists.digium.com/mailman/listinfo/asterisk-users To UNSUBSCRIBE or update options visit: http://lists.digium.com/mailman/listinfo/asterisk-users
