It would be great if the dialling rules for the 2820 could specify whether they were applicable to handset 1, 2 or both, so you could have a default set of rules that would treat both handsets the same but if, for instance, you wanted your caller ID to be different between a personal and business line, you could define the rules that direct calls to one SIP provider only to apply to handset 1, and those to the other SIP provider to handset 2.

At the moment I'm having to use a separate Cisco box rather than use the second line available on the 2820 purely because it doesn't offer this segregation.