For work I am going to try and restore the canned messages in some ISD5100 ChipCorder modules. We have some good ones and I hope to read one and overwrite the bad ones. The modules have a 2.8 volt regulator and I am not sure if the Teensy will just work have have issues talking to it via its I2C interface. Should my pull up resistors go to 2.8v or the Teensy's 3.3V? I am thinking of using an Audio adaptor with to store the analog messages in the optional flash chip. How long of a playback can I get ? If needed I could add a SD card I guess. The messages I need to restore are a only about 4 seconds each and there are about 8 of them.