Are either the Serial or USB ports opto-isolated?

[Anonymous user]

Everytime I look at the pc board for a smups 1500 ( or 1000, or 700 ) table-top I observe that the serial port is just about 2.5 inches away from the 115vac input. The USB circuit appears to be futher away, and are probably less likely to have the 115v reach it.
Since the serial, as well as the usb ports 'touch' one of my computers, I was wondering if the ups design also includes optical isolation?

[Anonymous user · Accepted solution]

Hello,
I do not know about optical isolation, but it is isolated. There is no electrical connection between the battery side and the AC side. 120v AC side and battery are galvanically isolated by the main transformer. There are about half a dozen relays and they're all controlled on 24v DC side and they all control the 120v side. The insulation break-down voltage is the lowest of the relay coil to contacts, PCB track and the main iron-core transformer at the bottom.

The LAN protection port found on some models is on it's own mini-PCB and it is not even part of the main board and there is no connection between it.

KVAr