Use tablet as handsfree for any Android Phone

[ComputingCode]

Hello there,
I would like some suggestions for a project. I have a car with a cassette radio. I want to install a tablet in the car as a head unit. Sound from the tablet will go into a "aux in cassette" that will be permanently inside the tape deck. What I am missing in this entire scenario is... an app that will allow me to connect my phone (android) via BT to the tablet and make/answer calls from the tablet. I will use the 3.5jack for microphone and audio (that will go into the cassette). I tested with "TabletTalk" but I can't seem to get the sound to move from the phone. Besides you need the app on both devices. Also Tethering went through my mind (via OTG) but that would mean the phone is getting charged and .. I kinda wanna keep my battery healthy.

Does anyone know how to use a tablet as a handsfree? (Mr Google does not give me a good answer)
If you need more info I am happy to give.
Thank you for the time.

 

[Dannydet]

Nope. Never gonna happen.

 

[Davdi]

If the car hs FM radio (most do), try one of the Bluetooth devices that plugs in the 12v outlet on the dash/centre console. I use one and they work very well. Mine has USB, SD card, 3.5mm Aux in and bluetooth handsfree and streaming. They're on EBay and Amazon for not much money.
Here are a few examples:
https://www.ebay.co.uk/itm/Bluetoot...reless-Handsfree/293005215588?epid=9034665675

https://www.ebay.co.uk/itm/Wireless...685169&hash=item5224ce9d3d:g:u-gAAOSwdJtdQQRs

There are a lot of them, just search for 'Bluetooth Hands free' or 'Bluetooth car kit'