Re: hmm, sorry, data cable question

what serial port are you using? usb-serial? a laptop one? you are not frying your mobile only because you are lucky: your com port fails to deliver the 12~15v standard to the rs232 and delivers 5v instead so the 7805 regulator fails to deliver 5v because it's a linear regulator with a high drop out (internal voltage loss- it is designed to work at at least 6 or 7v ) plus the diodes voltage drop and it's delivering 3.4v if your connect that cable to a good com port, it will drive the calypso at 5v and it will fry it. right now is delivering 2.5v on tx, and it seems that's just enough to drive the calypso serial TL;DR: get a usb->ttl3.3v cable and forget this one also, did anyone tried attaching a phone to a 5v cable to see if it really dies? 2011/5/24 Roy <roytiberius(a)gmail.com>