I have a Tablet S with 3g which I have started using on my commute to work.
I have found the GSM/3g functionality quite frustrating. It appears as though if the signal is lost the tablet does not reconnect when the signal is restored.
Once or twice on the journey the signal indicator in the bottom left will grey out ( no signal ) and not recover the signal until I interviene.
The indicator in the bottom right hand corner shows no signal i.e. goes dark grey ( despite being urban London ) until I either shut down and restart the tablet or occasionally go in to settings / mobile networks and untick and tick data enabled and data roaming.
The sim card is on O2 with unlimited data. I have (two) Dell Streak devices either of which happliy manage to operate on exactly the same route with the same SIM card i.e. might run slow on occasion but maintain connection to the internet / android market place. Same is true of my Blackberry 8300. APN is mobile.o2.co.uk. Under most circumstances the tablet will show full strength and indicate a 3G connection.
The WiFi functionality is disconnected in case of conflict.
Certainly the power management appears to be quite aggresive (always shuts down Wifi) won the Tablet S which is good. My assumption is that something is happening with that which means that the GSM unit does not attempt to reconnect.
I would have expect the tablet to better manage the situation of variable signal strength and maintain a data connection as a consequence.
If this behaviour is as it should be then I need to be considering another tablet perhaps which is a shame but I don't want to spend half my journey turning the tablet on and off.
Any suggestions ?