Parallax Board Of Education with Basic Stamp 2 installed

The Basic Stamp is a single-board computer (SBC) which uses a  PIC16C57
microcontroller. The on-chip 2K of ROM holds the BS2's PBASIC2
Interpreter. The actual tokenized programs written by the programmer
are stored in an external 2K EEPROM (Electrically Erasable
Programmable Read Only Memory).
Of the 20 I/O lines available on the PIC16C57, 2 are used to read and
write EEPROM memory and 2 others are used for serial
communications to the host PC for programming. This leaves 16
I/O lines, or pins, for the BS2 user. Of the 72 bytes of RAM available
on the PIC16C57, 32 bytes of RAM are available to the programmer
with 6 of these being used as 'registers' to control the input/output
pins. It’s important to understand that once programmed, the BS2 is
completely independent of the host PC.