No, they won't make you tell them who you are unless you want to. They may ask for your name out of politeness, but you do not have to give this to them. However, they would be able to track the call, so if they wanted to, there would be a high chance that they could find out who it was who called them whether you had given your name to them or not. But never worry about phoning because you think they would want your name, as this is more than likely not the case.