An internal wireless modem (kind of like what's in the palmVII) based on PHS technology and available only in the Japanese market (of course). It allows for decent connect speeds, and rated at 64k is faster than you standard V.90 modem. The logo looks kind like this, H"IN
So if your wondering about how the hell they get Edge-In out of H"IN, H is pronounced "eichi" and the " makes the "chi" in to "ji" so for a native-ish pronunciation 'eiji-een'