All other major networks and some MVNO's have visual voicemail. For the iphone base, it's very easy as it's a one size fits all sort of thing. After being with Vodafone for 2 years, the idea of going...
sixeyes It only works when your iPhone has signal, otherwise the caller gets sent to your usual voicemail. If you have signal and they leave a message it’s stored directly on your iPhone, of course it’s there regardless if you have signal or not afterwards because it’s all done on device.
Visual Voicemail is basically a server that stores your voicemail and sends it to you iPhone when you have signal. Three & Smarty don’t have the servers.