On Mon, Jan 17, 2000 at 08:11:35AM -0500, Eric Wood wrote:
> I guess you'd do this if you're sending *highly* compressable data, ie text.
> What kind of modem is that and does it offer compression at that rate??
It's a Diamond Supra-Express V90 external modem. They claim it'll do up
to 230400kbps.
I've currently got it on a port running at 115200 and it all runs fine.
Since things such as web pages tend to be uncompressed text, I thought
that things of that nature might download faster if I could get the
serial port to run at 4X the connect speed rather than at 2x. Some
"experts" do recommend trying to have the serial port speed > 2X the
modem connect speed.
I cannot tell if the trouble I had was the modem misbehaving at high
speeds, or the serial port, since I have only one of each that is
(claimed to be) capable of such high speeds.
When set up at 230400 I can connect to the modem with a terminal (I
use C-kermit) and type things to it but it doesn't seem to actually
understand what I'm typing. Only one time out of many did I get back
an "OK" from having sent an "AT". I've tried using irqtune to set its
interrupt to the highest priority but that doesn't help either.
It's not worth spending a bunch more money for a different serial card,
I was just hoping that what I had would work.
Thanks!
Fred
> >Out of curiosity:
> >
> >Why would you want to do this?
> >
> >Since with regular modems you are limited to rather slow data rates anyway,
> >you'll be hanging your CPU up dealing with the port NMI/IRQ's, let alone
> >latency issues...
> >At best you'll need to be sure that your software enables the maximum size
> >of the on board I/O buffer of the 16c550. The 16550a's were limited to 16
> >bytes...
> >
> >I hope that the byterunner is a PCI card (which I doubt since you mentioned
> >jumpers) since you'll really be taxing the ISA bus.
> >
> >From my prospective, you'll get BETTER performance from a lower DTE rate.
> >
> >-JMS
> >[EMAIL PROTECTED]
> >
> >
> >-----Original Message-----
> >Has anyone here used a high-speed serial port? I.e., 230400.
> >
> >I've got a serial board (Byterunner, 2 ports, 16c550 uart chips) which
> >has jumpers to double or quaduple the clock rate so that the speeds you
> >choose will be multiplied by either two or four. I've got a modem that
> >claims to work at 230400. But when i set the board to double speed last
> >night could not get reliable communications with the modem.
> >
> >If anyone has knowledge of how to do this I'd appreciate pointers.
> >---- Fred Smith --
--
---- Fred Smith -- [EMAIL PROTECTED] ----------------------------
But God demonstrates his own love for us in this:
While we were still sinners,
Christ died for us.
------------------------------- Romans 5:8 (niv) ------------------------------
--
To unsubscribe: mail [EMAIL PROTECTED] with "unsubscribe"
as the Subject.
