A close reproduction of the MITS 88-2SIO Rev 0 Serial I/O Board used in the ALTAIR 8800 and other S-100 computers. This board provides one or two serial ports using the 6850 ACIA. Although not an exact replica, this board is functionally equivalent to the original MITS 88-2SIO board. This board uses the same components and documentation as the original. RS-232, TTL, and Current Loop are supported.  Most components on the right side of the board are only required if using Current Loop. The 88-2SIO is compatible with a vast amount of Altair software, including CP/M and Microsoft BASIC.

This sale is for a bare PC Board. All parts are available and full documentation including assembly manual is readily available on the web.

This board was produced from scratch using KiCad 7 and an original 88-2SIO as a template. Prototypes were then made to confirm proper operation.

I am happy to accept returns if you are not pleased for any reason as long as the board is unassembled. You will need to pay return shipping only.