[geekmaster]

Originally Posted by dalvick

hello, thank you for answers
i use this without external power
http://www.ebay.fr/itm/RS232-To-TTL-...-/252399950706



and do the same think when i unplug 5v cable and use external!

terminal reset dont resolve it and with tera term ger the same issue

The only way you can use that adapter is if you run it with the RS232 side connected to an older PC (most modern PCs do not have an RS232 port), or with a USB RS232 adapter connecting that 15-pin RS232 connector to a modern PC. You must also use a level shifter circuit on the TTL (3-pin) side. This adapter uses 5v TTL and the kindles are 1.8v TTL). However, MAX232 chips are known to generally work okay when powered by 3.3v, but your adapter seems to derive its power from the RS232 interface (so no easy way to adjust it). Depending on how that green LED is wired into your circuit, it might cause problems (though it may just be a power indicator, which is fine).