Does 3911 provide a local switch for PC connection ?
The IP Phone 3911 does not have a local switch for PC Connection. The 3911 is comparable to the EOL 7902 and newer 7906 as far as functionality goes. There is some good info and a diagram in this doc;
Cisco Unified SIP Phone 3911 Administration Guide for Cisco Unified Communications Manager 6.0 and 5.1
Hope this helps!