Hi I would suggest that this is a very unusual way to do a serial card. There are a lot of PCIe cards out there that go straight to the bus. Amazon is awash in them. If you stick with the 1 or 2 port versions, you should not get anything to weird.
Bob > On Nov 5, 2021, at 10:14 PM, Rich Wales <ri...@richw.org> wrote: > > Angus wrote: >> /What timing issues did you have? I've used a similar setup on two old >> windows machines (one XP and one Win10) and I didn't see much difference >> between the built in serial port and the ones on the PCI serial cards. They >> were not PCIe./ > > The serial card I used (with unpredictable PPS signal timing) was a PCIe > card. But I think the more significant difference was that this PCIe serial > card was really a USB card with a serial-to-USB front end, and this protocol > conversion was the reason for the extra jitter. > > Old PCI serial cards came from a time before USB was common (or even > existed), and they sent the serial data directly to the PCI bus without going > through any intermediate steps. If we could find PCI or PCIe serial cards > which worked in this same way, we would presumably have the same high > performance as in the old days. However, there is very little incentive > nowadays for hardware manufacturers to do this; the few serial cards that are > still made today (after all, who really needs, wants, or even knows about > RS232 anymore?) generally cut corners by slapping a cheap serial-to-USB front > end onto a cheap USB card, and except for those of us who really need > accurate timing, none of their customers are likely to care or even notice. > > *Rich Wales* > ri...@richw.org > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an > email to time-nuts-le...@lists.febo.com > To unsubscribe, go to and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there.
