IP920 Operating Manual: Chapter 4 Configuration 17
UTC Time Offset defines whether the offset system is ahead or behind UTC
time. A “+” indicates local time is ahead of UTC time and a “-” indicates
local time is behind UTC time.
Before clicking on Synchronizes with SNTP Server, SNTP server should
have already been set to proper internet time server or network timer server.
See 4.3.2 for details.