Nokia 6165i User Manual page 203

When is my data connection dormant?
If no data is received for 10 seconds, the connection goes
dormant. When the connection is dormant, voice calls are
allowed. (The connection may become active again quickly.)
If no data is received for an extended period of time, the
connection will terminate.
Can I sign out of data services?
You can sign out without turning off your phone; however, you
will not be able to browse the Web or use other data services.
While signed out, you can still place or receive phone calls,
check voicemail, and use other voice services. You may sign in
again at any time. To sign out, go to Menu > Settings > Data
Services > Disable Data Services in your phone's menu.
Section 3B: Data Services 177