CompuPro - Interfacer I
The Interfacer-I was the first of a series of popular CompuPro  Serial I/O boards.
 

This board incorporates reliable LSI technology UART chips to perform the basic serial-to-parallel and parallel-to-serial conversions necessary for this S-100 dual channel I/O board. By using these UARTs, the CPU is freed of the time consuming drudgery of performing serial I/O operations by software techniques. Because of this, I/O operations are far more reliable and easier to implement.

In addition to the UARTs, several other features are included to make this board extremely flexible and easy to use. These features include an on board crystal controlled dual baud rate generator for reliable baud rates independent of your CPU clock speed, conversion to TTL, current loop and RS-232 levels for interfacing to almost every kind of serial device, and hardware/ software programmability for power-on operation and easy parameter modification.

Other features standard to all CompuPro boards include thorough bypassing of all supply lines to suppress transients. on board regulators, and low power Schottky TTL and MOS technology integrated circuits for reliably cool operation. All this and sockets for all ICs go onto a double-sided. solder masked printed circuit board with a complete component layout legend.
 
The manual for this board can be obtained here.

 

Other CompuPro S-100 Boards
CPU8085-88  CPU86-87  CPU-Z  Disk1  Disk1A  Disk1B  Disk2  Disk3   EconoROM2708  Interfacer 1  
RAM Boards   Interfacer 3  Interfacer 4  Interfacer II  M-Drive  MPX-Board  PC-Video  
System-Support1  System-Support2   SPIO  Spectrum  SP186   CPU-286   68000  32016  SPUZ