The HHT was the predessessor to SDS and SDS runs diagnostics on early systems by running an emulation of HHT on its screen, complete with the crude graphics capable with a hand held.

One could probably buy a clone for what a used HHT would cost, but there were a number of tools that emulated the early HHT. I just sold an old CS2000 last week for $500. The AST retriever would also do the job. Sold one of those years ago. I have used a SDS since they first became available in about 2001. Before that is was the above two tools.

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Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician