Ever noticed this with your Motorola MPX 220 or Audiovox SMT 5600 :-

Problem: After you cradle your Windows Mobile based Smartphone, Activesync will connect and synchronize fine but automatically disconnect after 2 or 3 minutes even though the device is cradled. Also did you notice one common thing between the above mentioned devices? They are available through Cingular.

Resolution:
You need to disable Cingular Expressmail’s Push Feature on the Pocket PC.
Go to Start—>More—>XM Settings—>Sync Preferences—>And Uncheck Enable Push

Now when the Smartphone is cradled, Activesync will not disconnect