Can Android act as a WiFi Access Point while the cellular radio is turned off?
YES.
OPTION #1: Use your Android phone without SIM cards(s) inserted
OPTION #2: Disable mobile data & Enable call forwarding
You can use a WiFi Hotspot while your **mobile data is disabled**, to avoid disturbances you can set call-forwarding.TURN OFF MOBILE DATA
Bring down the quick settings panel with a double swipe-down gesture (or a two-finger drag) of the notification bar.
Turn on Hotspot and adjust your hotspot settings as needed
Tap on your mobile network indicator in quick settings panel this opens Mobile data
Toggle mobile data off
In your notification bar your can now see the WiFi hotspot indicator on the left side and on the right side a cellular network strength icon with an exclamation mark.
Connect to your Hotspot from your other WiFi enabled device
REDIRECT INCOMING CALLS TO YOUR VOICEMAIL / ANOTHER PHONE:
Launch Phone app
Access settings by pressing ... and then Settings
Select Call settings
Select Call forwarding
Setup a Always forward rule to your voice mail or another phone number or voice mail
OPTION #3: Learn how to find good apps in Google Play. Make sure you read descriptions ;-)
As in regards your question about apps, please use Search in Google Play. Customer reviews and ratings usually provide fair guidance about app quality.
If you find an app not working (like supposed in your case "Cell Radio ShutOff") you might want to give a fair constructive comment with suggestion about app/widget improvement.
Most developers use customer's feedback for improvements and development.
In this case the developer was clear about tested devices and even posted the code to shut off the Cell-radio by dialing a code:
If this doesn't work with your phone you can access a builtin interface which has the same option. If you dial *#*#4636#*#* in Phone it will pull up a menu that will allow you to shut off the cell radio.
If above was missed or is unclear, please follow steps below.
OPTION #4: DISABLE / ENABLE CELL RADIO USING TESTING APP
- Launch Phone app
- Dial *#*#4636#*#* to launch Testing app
- Select Phone information
- Scroll down to find button TURN OFF RADIO and press it Cell strength indicator will appear empty.
Repeat and press TURN RADIO ON to to enable cell radio again.
Note: Before turning off cell radio you might want to set appropriate call-forwarding setting a when unreachable rule. This must be set before you turn off cell-radio.
Important notes:
- Depends on the Android Device and WiFi hotspot application on that device.
- With dual SIM phones additional steps might be required.
- Details above are based on: Nexus 5; Android version: 5.0.1 (Lollipop)
Hope this helps.