Using a 4g SIM card in a 3G phone

[Justin schrader]

I am trying to use my iphone 5s SIM card in my Casio ravine 2 but the I phone is 4g and the Casio is 3G. How do I get the card to work in the Casio?

 

[Trave]

If its a 3g phone its a 3g phone,if its a 4g phone its capable to use 3g sim,so I think my answer is you can't,its more because of the hardware not the software,so you cant do much here.