Vector Graphic - Bitstreamer II
This was the main IO board Vector Graphic used to communicate with its printers.

The Vector Graphic Bitstreamer II Board was an all-purpose input/output board for S-100 systems. It offered three serial I/O channels and 2 8-bit parallel input/output channels for Interfacing with multiple peripheral devices such as printers, modems, and terminals. It also offered a 55 H2 real-time clock which can interrupt the CPU for functions such as sharing of the CPU by several users or peripherals.
 
They used the term "channel" rather than "port" to avoid confusion caused by the fact that each serial channel makes used of two I/O addresses, which are often called I/O "ports."
 
The CPU sends data to the serial and parallel channels via I/O addresses. The I/O addresses used by the board can be changed as a group. The board uses the eight I/O address x2 to x9 (in hexadecimal notation) , where x Is any digit from 0 to 7. You specify the value of x by jumper.
 
The Bitstreamer II Board did not come with any software for specific applications, though Vector Graphic supplies certain items of software that make use of  its features.
 
The manual can be downloaded from here.