USB-492
Tektronix 492 USB Interface
I have a Tektronix 492 without GPIB. This project adds USB connectivity to the Tek 492. It can download a full sweep in about 200ms. It can't read any configuration from the instrument, so it's not a real replacement for GPIB, but it would be possible to emulate the control code and duplicate the front panel controls on the computer.
USB-492 PCB. The USB connector is on the other side.
This is a simple board with an AT90USB82 microcontroller. It plugs into the accessory port on the 492 and gives the host direct control over the instrument bus.
Schematic
Spectrum of a TV station graphed in Octave.
Design Files
Use these at your own risk. As you can see in the photo above, the crystal footprint is wrong and I hacked a larger crystal onto the board.
I suggest you read the sections in the Tek 492 service manual that describe the instrument bus and microcomputer debugging. Timing diagrams and all register bits are described in the manual.