Paul in Houston TX wrote:
Paul wrote:
Paul in Houston TX wrote:
J. P. Gilliver (John) wrote:
Another point is that, unless towards the end of the '9x period, they
probably connect via the parallel port: virtually all more recent
laptops/netbooks don't have those, and I've been told even some
desktops
don't. (You can get USB-to-parallel adapters - "cables", but there is
some electronics in them - but they vary, and may not work with all old
hardware.)
Good point!
My 2 yr old MB does not have parallel or serial ports.
Tried a USB to parallel adapter with my old HP printer / scanner
and it would not work. Ended up getting a pcie parallel card
which works great.
Cannot use my external USR phone modem because it requires a
serial port and the MB does not have any available pcie ports.
The MB does not have a built in analog modem, so no phoning for me.
Have you checked for a 2x5 serial header ?
I bought a USB to RS232 adapter, used it for a day or
so, when I happened to be looking inside the computer
case and noticed a 2x5. I went back and checked the manual,
and damn if the motherboard didn't have a single serial port
on it. (That 2x5 has a different pattern than the USB headers.)
The reason things like that can show up, is due to the
continued use of SuperI/O chips. This is more popular
on home-build PCs, where the manufacturer wants to continue
to have a hardware voltage monitor (for Speedfan etc). One
of the bonuses, is the SuperI/O has a serial port. The manufacturer
still has to pay for an RS232 interface chip, to convert logic
levels into +/-25V max serial I/O. So they still have th
throw a TI 75232 onto the board, to make it work.
I uses an existing ribbon cable, plus a DB-9 I still had
sitting here, made an adapter cable, and that's my serial port.
You can also get serial ports on plugin cards, with
assignable addressing. So that the port will be recognized
at the usual address.
The USB to parallel port, is limited to one flavor by
the nature of the software stack. It isn't a hardware
issue as such - there's no way to support all possible
protocols, with the way the USB class works for the thing
now. It is really a "USB to printer" design, where the
printer is a subset of all possible flavors. Whereas
the PCI Express version, the stack is not limited in that
way for it. So more stuff can work. (Even my JTAG programmer
cable would work on there. I have a JTAG cable that runs
off a parallel port. And my PCI Express card drives that.
I've tested it.)
Paul
It's a GA-X58A-UDR3.
Has everything else but serial header.
I have an old AMD single core computer that I use with
a USR external modem.
Company laptop #1 has a built in software modem that connects
to around 10% of the scada equipment so I have to use the
old comp and USR external for the other 90%, which is a pain
since the data belongs on laptop #1.
What I really need is a USB modem that I can use with the company
laptop #2 that does not have anything except usb ports.
My usb to serial converter does not work with an external modem
however it does work with direct connect RS-232 to the scada equipment.
Your motherboard does have a serial port, but you
can't use it.
The IT8720F has a serial port. It would need a TI 75232
level shifter, to be ready from a hardware perspective,
but the kicker is, it cannot work without a BIOS code
change. Someone with a configuration tool might be
able to turn it on. They can't leave it turned on,
because a user might mistake it for working hardware,
so it "disappears" from the address space, BIOS table
and so on.
(Block diagram if IT8720F - I'm guessing that's the one...)
http://ts3.mm.bing.net/th?id=JN.UV6i...g&pid=15.1&P=0
And it's funny, as they included a Firewire chip, which
puts the board in an upper tier from a hardware
interface point of view. If they could pop for
a Firewire chip, they could pop for a level shifter.
I can't begin to guess why the modem doesn't work.
Any USB to serial, should have the full DB-9 set of
interface signals. While they do make USB to TX/RX/GND
TTL level adapters for cell phones, I doubt they'd bother
doing one with RS232 levels with that limitation, as
there'd be practically no use for it. You really need
the flow control, to get the best possible performance
from a bad situation. Perhaps if you had one of those
LED gizmos, that monitors serial port signal levels,
you could figure it out.
Paul