Using Home Phone with this 4G/5G router?

RealGem

Hi 

I am thinking of buying this router to use with a separate unlimited SIM: The ZTE MF286R, LTE CAT6/4G Unlocked Wireless Router

https://www.amazon.co.uk/ZTE-MF286R-Unlocked-Wireless-Staycation/dp/B08VJMWTCM/ref=cm_cr_arp_d_product_top?ie=UTF8&th=1

This YouTube video below says you can plug a home phone in it. So wait... I can use my former VM landline phone on a router with no monthly phone line charge?!

How does that work please? Is it VOIP? (Feel free to dumb it down! - I know NOTHING!) 

https://www.youtube.com/watch?v=GKCORqPx3T8&ab_channel=eFones

And what will determine the phone number I get? 

Any other router advice would be appreciated. 

Thanks a lot

grumbler

>>  Connect a phone to a 4G router

- some other router, but is worth having a look.

With regard to the number, I think it's the number allocated to the SIM.