To access the field test display in iPhone, dial *3001#12345#*. If you are already in a call, just hit "add call", enter the number above and hit call; the phone will go into test mode, but keep your call connected.
The following pages are available in iPhone field test mode:
GPRS Information & PDP Information
Call Information & Versions
iPhone provide basic network information in field test mode. Timing Advance (TA) is missing in the network information and cell information is a disadvantage.
iPhone 3G also get the field test mode. I don't have a 3G iPhone and cannot provide you detail information. A screen capture is found from the web:
There are 3 sections:
UMTS Cell Environment
GSM Cell Environment
GSM Cell Environment should be the old GSM pages. UMTS Cell Environment is of course 3G stuff. I have no idea what is MM Info. In GSM terminology, MM can refer to mobility management. If you have and 3G iPhone, please leave me some info in the comments :).
Symbian 9.1/9.2 NetMonitor (FTD) for hacked phone