Here is the manual in PDF, and here are the design, software and documentation files: current_version (~1.8MB).
(the filename of the current version reflects the BTS6120 version, the extension ROM version and the FPGA code version)
This device's design is made available under the terms of the GPL.
There is lots of reusable, fairly modular VHDL IP in there - a configurable UART, PS/2 keyboard to ASCII, ASCII to VGA video, serial terminal and other good stuff. It's mostly wrapped in code that interfaces it to a PDP-8 bus via IOT's, but it's not specific to that bus.
The construction of the board is straight-forward, but since it is built with surface mount components, good tools and some practice are strongly recommended before tackling it. Most parts are half pitch (0.05" lead spacing), and are easily solderable with a fine-tipped temperature controlled iron and fine solder. A few parts are fine pitch (0.5mm lead spacing) and can be difficult to solder without strong magnification and a steady hand.
I am no longer able to supply kits, parts or assembled units.
However, some people in the Yahoo SpareTimeGizmos group have built a new version of IOB-6120; please enquire there.
These are implemented in the revised SBC6120 EPROM set, and are useful even without an IOB6120. The revised EPROMs are larger than the originals, so 27C256 or 27C512 EPROMS must be used instead of the 27C64's that were originally specified.
Persistent Partition map - if ramdisk memory is installed via an IOB6120 or other hardware (e.g. the Spare Time Gizmo's ramdisk board), the partition map is saved and restored from it.
Partition Compare (PE) command - checks two partitions for equality, for example after a PC (partition copy) command.
IDE boot unit - in previous versions, the Boot command would always boot from partition 0. This has been changed to boot from the partition mapped as unit 0 using the PM command.
Extension ROM support - a system for extending BTS6120 has been added. When the system starts, a check is made for an extension ROM, and if found, it is installed. The extension ROM can add commands to BTS6120, add function calls for application program use, or modify (hook) existing functions in the EPROMs.
Flash Download (FL) command - if extension ROM as described above exists, it can be initialized by downloading a file over the serial port. Currently only 28Fx00 ROMs are supported, but 29Fx00 types could be used with minor changes.
Disassembler - adds a new X command to disassemble from memory, and enhances the TRace command to display mnemonics as you step through a program.