#Basic Stamp serial interface
The Basic Stamp 2 expose a RS232 serial port (some models have an integrate USB-to-Serial circuit) that is used for the download of a new program in the EEPROM and for debug. The RS232 standard work in the range of -15 to +15 volts.
The BS2 have a RS232 adapter with a circuit that change the -15/+15V range to the 0/5V need for the PIC.
The Basic Stamp 2 serial port comunicate at 9600 baud, None, 8, 1 idle and use 3 line: RX, TX and DTR, there are also a loop back of RTS to DSR. The Basic Stamp Editor provide a debug window, the output of the DEBUG commands are sent over the PIC TX line and are shown here.