I'm interested in using Lync for voice communication. I gather the software supports SIP trunking as long as your SIP provider supports TCP (I'm using 2talk which does). So I've gone ahead and ordered a basic Lync 2013 online account but can't find anywhere where you set that up. Is this only available on the on-premise version of the software and not the online version?

As a side question, I currently have 2talk configured on Android with the built-in SIP client and getting poor battery life. I gather switching to TCP instead of UDP helps increase battery life because it changes to sending a keep-alive signal every 20min or so instead of every min or so for UDP. Is this correct with 2talk and Android SIP, and is this only used for SIP communication, but for the actual phone call does it still use UDP?