I guess this is more about being funny than actually useful to most of you guys. Nokia just released an interesting app for Lumia 920T users on China Mobile. The app only does one thing: to lock the phone to either 3G or 2G network.
This may raise some eyebrows, since normally one could select what kind of network he wants in the system settings of Windows Phone 7 and 8. But no, that doesn't apply to China Mobile's Lumia 920T, which stays on 3G network by default. The 2G/3G/4G switch was removed by request of the carrier, probably in order to keep as many users on its 3G network as possible.
The lack of a network switch, combined with the carrier's weird 3G network itself, resulted in a fair share of frustration. China Mobile runs its homegrown TD-SCDMA network for 3G, which surprisingly is not compatible with the GSM 2G network, which is supposed to be a global standard. Therefore all TD-SCDMA phones actually come with two separate cellular network modules, one for GSM, the other for TD-SCDMA. When a phone finds itself outside TD-SCDMA coverage, it will try to activate the GSM module. Frequent activating and deactivating of cellular modules eventually cause the phone to crash and reboot. The frustration is shared by a whole fleet of TD-SCDMA devices, not just Lumia 920T. I've heard the rebooting problem is particularly bad in rural area, where TD-SCDMA coverage has quite a lot to be desired.
With Nokia's network locker app, a Lumia 920T owner could choose to just lock his phone to GSM. China Mobile enjoys epic GSM coverage which supposedly stretches all the way up to the top of Mount Everest. By staying away from TD-SCDMA, one effectively gets much more stable connectivity, therefore significantly reduced crash/reboot rate.
Although this is somewhat ironic, it still shows Nokia is working seriously on addressing local needs. This app now seems to be getting volleys of positive reviews and gratitudes in the Chinese facet of Windows Phone Store.