Connecting an old scope to a computer


A friend of [Michael]‘s said his company was getting rid of some old lab equipment and asked him if he wanted a very large and very old digital storage oscilloscope. A ‘hell yes’ and we’re sure a few beers later, [Michael] found an old Gould 200 MHz four-channel scope on his bench. Even 20 years after its production it’s still a capable tool, but the serial ports on the back got [Michael] wondering – would it be possible to plot the screen of the scope on his computer?

The scope has three ports on the back – GPIB, miscellaneous I/O, and RS423. The latter of those ports is similar enough to RS232 that a USB to Serial converter just might work, and with the help of a null modem cable and a terminal, [Michael] was able to connect to this ancient scope.

In the manual, [Michael] found a the serial commands for this scope. The most useful of these is a command that prints out the contents of the scope’s trace memory as a series of 1-byte integers. With a short bit of PERL programming, [Michael] can create a PDF plot of whatever is on the scope’s screen. It’s formatted perfectly for Gnuplot, MATLAB, or even Excel.

Awesome work, and especially useful given these old scopes are slowly making their way to a technological boneyard somewhere.


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