The Serial POD for the OtterBox 1900 PDA Case adds an external serial connection and charging point to the case. The Serial POD only works with newer model HP iPAQs with a standard 22-pin connector. The POD easily installs in place of the rubber plug on the bottom of the OtterBox 1900. Null modem-style serial devices (GPS, survey equipment, etc) can be connected to the PDA through the DB9 serial connection on the POD. The POD can also be used to sync the PDA when used with a null modem adapter! A 4mm power jack is incorporated into the POD so that the PDA may be charged using the standard HP iPAQ AC addapter without removing it from the case. Please note: The serial connection is rated as water-resistant, not waterproof. The case is not submersible with the serial POD attached. The integrated cap can be used to cover the connection when not in use.