[vcf-midatlantic] Heath H-11 line time clock question

Richard Cini rich.cini at verizon.net
Tue Apr 19 09:48:49 EDT 2016

All —

I just hit on an anomaly with my H-11 so I wondered if there was anyone on-list with experience with the H-11, although it crosses-over to DEC. In short, I added an Emulex SCSI card and SCSI2SD to my H-11 so I could run RT-11. The TU58 emulator was way too slow. 

RT-11 won’t boot with the LTC enabled, and the Emulex manual specifically says it should be disabled at the CPU card. But, I want to run Kermit (to enable easier file transfers rather than dd’ing a new image to the SCSI2SD each time), and Kermit for the PDP-11 requires the LTC.

The H-11 comes in two versions – one with an LTC switch and one without. Mine doesn’t have the switch, but one was added, performing the same function electrically (grounding the base of the transistor driver to the BEVENT signal). If I put a counter on the BEVENT pin, I get 60Hz with it enabled and 150Hz with it disabled. This is the anomaly I wanted to check out with any other H-11 owners.

Alternatively, if anyone knows of a file transfer program for RT-11 (SJ, FB monitors only) then maybe that’s an option. I’ve seen an XMODEM program but it uses TSX.



Rich Cini

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