As the title already told, you need to have hacked phone in order to activate the netmonitor for field test display in Symbina 9.1/9.2 phone. Hacked phone allows you to see the hidden system folder inside the phone. You can then copy the necessary files into corresponding folders as listed below.
Hack symbian phone
Why we need to hack? It's because Nokia hide system folder/files and do not allow us to install unsigned applications. To use netmonitor/ftd program, we need to hack the phone first. Therefore, if you feel unsafe or do not want to hack the phone, you can find other netmonitor infos in this blog.
When Nokia made new firmware to kill the old AppTRK method to hack Symbian phones, the hackers responded with HelloCarbide. ROMPatcher is a program to toggle the Symbian locks on your phone on and off, and comes with a bunch of plugins to customise menus, silence the camera shutter sound, and more. Installserver lets you install unsigned programs on your phone so you don't have to deal with the slow, clumsy Symbian Signed bureaucracy.
Just use google to search for the tools and you can easily hack your symbian phone painlessly.
Download netmonitor program
Download ftdALLSymbianV3.zip from the following link:
ftdALLSymbianV3.zip (Updated on 16 Sept 2011)
The tool is tested on:
For icon in symbian9.1 (n73/n80/e65 ecc ecc) use the 3 files in attachment (ftd symbian9,1 icon)