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From: Terence on 3 Dec 2007 22:07
I have simple mechanical devices which I control on an RS323C port
using a simple
Write character, Read string, (optional write character for re-
transmission of string, read string), and repeat, as only protocol
(but check interface beteen operations).

Device manufacturer says you can just plug the cable into a serial/
usb adapter, then that into the USB port!

So how do I comunicate with theUSB port?
Before I communicated with COM1 (to COM4) as serial port 0 (or 0 to
3), using service interrupt 14H, for setting baud rates and reads or
writes, and checking the "modem line signals" for error, data read,
etc.
..
Now what do I do with USB ports?
From: robertwessel2 on 3 Dec 2007 23:45
On Dec 3, 9:07 pm, Terence <tbwri...(a)cantv.net> wrote:
> I have simple mechanical devices which I control on an RS323C port
> using a simple
> Write character, Read string, (optional write character for re-
> transmission of string, read string), and repeat, as only protocol
> (but check interface beteen operations).
>
> Device manufacturer says you can just plug the cable into a serial/
> usb adapter, then that into the USB port!
>
> So how do I comunicate with theUSB port?
> Before I communicated with COM1 (to COM4) as serial port 0 (or 0 to
> 3), using service interrupt 14H, for setting baud rates and reads or
> writes, and checking the "modem line signals" for error, data read,
> etc.
> .
> Now what do I do with USB ports?


If you're on the raw hardware, you'll need to get a USB host stack
installed that can talk to the USB device, and then have it emulate an
Int14 serial port. Some USB support is available for DOS, but I'm not
sure how much will be usable for serial ports. Frankly, I've not had
many happy experiences with USB support under DOS. Some BIOSs do
support a certain amount of emulation of legacy devices with physical
USB hardware (keyboard and mouse, most commonly), but I've never seen
(not that I've really looked) that support of USB serial devices.

You may be better off going with a PCI serial port card if you need to
run under DOS, and PC Card/PCMCIA are available for laptops, although
those will require a Card Services stack installed on the PC. Do
check on compatibility in either case. For the PCI card, you'll
probably have to run a manual PCI configuration to get the ports set
correctly, if you can't address the device at the location where PCI
autoconfig happens to dump it, and you just want to make sure your
chosen vendor will support you.

If you're running under Windows (in a DOS box), the drivers included
with many of the USB serial dongles provides DOS emulation, but it's
typically not enabled by default. In most cases, this is a tab on the
devices Device Manager properties page.

OTOH, if you've got a Windows version, or port in the works, this is
trivial - the USB serial device is simply a particular device name,
usually defaulting to something of the COMxx form, you just need to
support the correct name. In some cases you might want to use the
TAPI interface as well, although it sounds like that not something
your application needs.
From: Dirk Wolfgang Glomp on 4 Dec 2007 00:25
Am Mon, 3 Dec 2007 19:07:55 -0800 (PST) schrieb Terence:

> I have simple mechanical devices which I control on an RS323C port
> using a simple
> Write character, Read string, (optional write character for re-
> transmission of string, read string), and repeat, as only protocol
> (but check interface beteen operations).
>
> Device manufacturer says you can just plug the cable into a serial/
> usb adapter, then that into the USB port!
>
> So how do I comunicate with theUSB port?
> Before I communicated with COM1 (to COM4) as serial port 0 (or 0 to
> 3), using service interrupt 14H, for setting baud rates and reads or
> writes, and checking the "modem line signals" for error, data read,
> etc.
> .
> Now what do I do with USB ports?

With UHCI, OHCI and EHCI drivers?

http://www.stefan2000.com/darkehorse/PC/DOS/Drivers/USB/
http://www.georgpotthast.de/usb/

Dirk
From: Terence on 4 Dec 2007 17:13
I tried these two sites.
The links from the first (to new links, which looked promising) all
failed as "URL not found"..
The second is not applicable to the problem and I coudn't locate the
Forum related either.

The first link desired, was to a supposed routine source to be
assembled that would search for connected USB devices, but could not
itself be located. Pity; could use that as a starting point.

Anybody know the names (as per COM0) or how to find them (suggestion
is COMxxx) for connected devices?

I checked with the manufacturer. Says the protocol in unchanged
between serial and USB plugged devices, which seems strange. Don't
think they knew what their engineering side actually provides the
buyer to make these things work the way They (not me) uses them. I
haveormal serial models - no problem, but they will stop making them.
From: robertwessel2 on 4 Dec 2007 17:54
On Dec 4, 4:13 pm, Terence <tbwri...(a)cantv.net> wrote:
> Anybody know the names (as per COM0) or how to find them (suggestion
> is COMxxx) for connected devices?


Try device manager. And remember that those names don't directly
correspond to the Int14 port numbers. Alternatively, fire up
HyperTerminal, the USB device should show up in the list of devices.


> I checked with the manufacturer. Says the protocol in unchanged
> between serial and USB plugged devices, which seems strange. Don't
> think they knew what their engineering side actually provides the
> buyer to make these things work the way They (not me) uses them. I
> haveormal serial models - no problem, but they will stop making them.


That just implies that their USB device looks is basically the product
of the old serial device, a serial port USB dongle, and some epoxy.
Which means that for Windows applications, it's just a matter of
adjusting the device name - it's still a serial port, accessible via
the traditional Windows APIs.
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