Original serial and parallel ports on the original IBM backplane were I/O port mapped, not memory mapped. There were discrepancies between port numbers between the true IBM I/O port numbers and "clones". Ports 3F8 and 2F8 for COM1 and 2, 3E8 and 2E8 for COM3 and 4. On a true original IBM, the first parallel port was 3BC, while most clones used 378 for the first parallel port. Note that these are input/output mapped, NOT memory mapped.
I'm not sure that PCI and PCIe serial and parallel port devices are truly I/O mapped (probably not), or memory mapped, but in either case, they are not true serial or parallel hardware devices, but something that emulates them. PCIe is itself a high-speed serial interface, so there must be some interpretation. Of course, even the older ISA cards ended up using ASIC devices to emulate serial and parallel ports, but that was hardware based. 73, Terry, N4TLF Sent from tfox iPad > On Jan 5, 2016, at 5:54 PM, Joe Subich, W4TV <[email protected]> wrote: > > >> On 1/5/2016 5:32 PM, Doug Person via Elecraft wrote: >> A 4-port card is NOT a native RS-232 port. PCI is just another bus >> add on. > > *Absolutely incorrect*. A USB to serial converter *of any kind* - > other than the Edgeport products - can not do 45.45, 50, 75 or 100 > baud RTTY. All of the multi-port RS-232 PCI and PCIe cards handle > that task with no problem (although Windows will set 45.45 baud to > 45 baud because the API is integer based). > > PCI and PCIe based serial and parallel port cards are true memory > addressed ports like motherboard or (obsolete) ISA bus ports - not > USB devices that suffer from latency and driver buffer issues. > > 73, > > ... Joe, W4TV > > >> On 1/5/2016 5:32 PM, Doug Person via Elecraft wrote: >> A 4-port card is NOT a native RS-232 port. PCI is just another bus add >> on. There no difference between running 1 or 4 USB to RS-232 >> converters. You can buy a 4 port FTDI converter that runs off a single >> USB port from Amazon that will run everything you could ever want. I >> run 80's vintage lab equipment off them and they don't know the difference. >> >> Also, don't get Windows 7 or 8. Windows 10 is the only choice for >> Windows. 7 and 8 are obsolete and support will get lighter and lighter >> and then vanish completely. >> >> Doug -- K0DXV >> >>> On 1/5/2016 12:24 PM, Cliff Frescura wrote: >>> I agree with N1MGO, >>> >>> I've come full circle on this one and am in the process of removing >>> all of >>> the USB/RS-232 converters in my setup and reinstalling a 4 port card >>> that I ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [email protected]
