http://qkpm2ov2rjhjkhfsftskqho77uj5rewd5y44unkf6cb7tdhaxwcvh2id.onion/books/apc/APCUPSD%20User%20Manual.html
We'll describe the possible values here, because they're
a good way to explain your UPS's single most important interface
property: the kind of protocol it uses to talk with its
computer. apcsmart The 'apcsmart' protocol uses an RS232 serial connection to pass
commands back and forth in a primitive language resembling
modem-control codes. APC calls this language "UPS-Link". Originally
introduced for Smart-UPS models (thus the name 'apcsmart'), this
class of UPS is in...