New Delhi: Yes You can Use Jio Sim In 3G Smartphone With Help of Small steps.
First step to download Shortcut master android application,
After download shortcut master simply install in your android device.
Now open this app and select engineering mode or service menu from main menu.
Here find system APP OPTION if this option is not available then dial *#2263# from dialer app. Now Go To Key Input And Enter 0000 and Wait some times.
After that select System app option and you need to change LTE bands.
Now go to Select - Protocol - NAS - Network Control - Band Selection - LTE Band and select Band 40.
After that restart your 3G phone and enjoy reliance jio 4G sim in your 3G phone.
*Roaming charges will also be zero
*Jio will offer data at Rs 50 per GB (base rate) against Rs 250 per GB charged on average by other operators.