So this is a SIP phone? Good luck... Mitel doesn't have SIP firmware available anymore and unless you are multilingual, trying to flash one over is almost impossible, the English Language file is more allusive than a 6-leaf clover. Best bet is Polycom SoundPoint series, 450, 550, 650, or VVX410 are my top choives, they all have clearly superior audio in all regards, and I am a 20+ year Mitel fanboy!