TOPIC: Make Telephone Field Required

I have tried to poke around in the dtregister.php file to see where I can change the phone field to become required (at least 11 characters wold be ideal) It's not working - any guidance would be gratefully received

well, between different payment gateways, individual and group registration options, there are many different forms represented in the component files. Which forms are you looking at wanting to make phone required?

For the moment we are using no payment gateway at all (will probably move to PayPal when the client is confident this is working) In other words all events are priced zero and we want to make telephone filed required (at least 11 characters)