About the project

Over the years, almost all P7001 have been separated from their minicomputers. So was mine when I got it. Still a nice collector’s item, but without all the main features degraded to a showcase model.

Since I couldn’t find an original computer, I decided to hook up a modern one to the P7001. Tektronix offered various interface types to connect the unit to different kind of controllers:

Name	Part Numbers	Usage
CP-Bus	021-0116-00 021-0117-00	DEC PDP-11 based machines (Original and Tek branded)
CP-Bus	021-0113-00	Data General Nova
31	021-0127-00	Tektronix 31 Calculator
4010	021-0175-00	Tektronix 4010 series Graphics Terminals
CAMAC	021-0146-00	Universal interface for the CAMAC standard Developed in cooperation with CERN
GPIB	021-0206-00	Universal interface for the GPIB standard Developed for the 4050 Computer series

The problem with most of these interfaces is that they are proprietary and it’s not possible to connect them to a modern computer. The only exceptions are the CAMAC and the GPIB interfaces.

I couldn’t find any information about the CAMAC interface, but it’s relatively easy to connect a modern computer to GPIB devices. But the subsequent tests revealed a big problem: communication speed. GPIB is by far the slowest of all available interfaces. About 125,000 data words per second can be transmitted via the CP Bus interface, while the GPIB bus is limited to about 50 data words per second - a factor of 2500. The X/Y mode and the controller-based signal averaging are practically unusable with this interface.

There were some other issues like bugs in the firmware of the interface and modern GPIB adapters not being 100% compatible with older devices. At the end, there was only one way left to go: I had to construct my own interface. The pandemic gave me some free time and the Teensy 4.1 provided an ideal basis for my idea.