I am planning on installing a PBX in my home. My partner is Mexican and when her family call I want them to be routed in Spanish. I don't want anything flashy, so I thought 3cx would be perfect. However, the documentation says that I must have a fixed ip. Why is this? My VoIP provider, Voipfone, don't require this so why does the PBX. I'm now having a look at pbxww from didww.com. Does anyone have any knowledge of this?