Sanyo SPRINT PCS VISION SCP-2400 User Manual page 230

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 time, the connection will
be terminated.
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 Sprint PCS
Vision 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 Settings >
PCS Vision> Disable Vision in your phone's menu.
214 Section 3B: Sprint PCS Vision