On Sun, Jan 26, 2020 at 2:59 PM Mattis Lind via cctalk <cctalk@classiccmp.org> wrote: > Hello IBM BSC Experts!
I used to be one 25 years ago, but it's been that long since I've even set up a BSC line. > I am trying to figure out the CRC algorithm used by IBM BSC... > > From this document ( > http://bitsavers.trailing-edge.com/pdf/ibm/datacomm/GA27-3004-2_General_Information_Binary_Synchronous_Communications_Oct70.pdf > ) > I get that the CRC calculation is reset on SOH (01h) or STX (02h) and > accumulates until and including the ETX (03h). (excluding any SYN (32h) > characters). That's a good document. What we used as our "gold standard" in the 80s was a "Data 100" manual for a 3rd party BSC workstation. The documentation went way beyond CRC-16 and message formats. It delved deeply into the whole protocol. I don't remember the vendor, and I know I don't have a scan of it. I was not able to quickly find a copy online but I admit I didn't search more than a few minutes. It would be a good resource to locate. -ethan
