Synchro AT is used to schedule synchronization. One use case is where you have an offsite server running automated uploads to websites. The upload server can be programmed to synchronize automatically on schedule so that listing information is kept up to date.
In More > Synchronize > Advanced > Synchro AT
Click Add to schedule daily synchronization events using 24 hour clock format.
Click Update Now to synchronize on demand.
When Synchro AT is running, that instance of SalesPartner is busy but you can open a second instance (check that mulitple instances is enabled in INI Settings > Setup).
Synchro AT will systematically synchronize against every saved server profile. This allows you to fetch changes from multiple locations.