improving transport over lossy links ?

Brian Candler B.Candler at pobox.com
Sun May 21 17:15:27 UTC 2006


On Sun, May 21, 2006 at 11:09:23AM -0400, Mike Tancsa wrote:
> The internal USR seems to correctly see the carrier drop and PPP 
> hence sees it.  However, the 2 external Intels I am experimenting 
> with on the USB serial ports do not.

USB-serial adaptors tend to be very broken, unfortunately. I don't know
about under Windows, but under FreeBSD/Linux where drivers seem to be
reverse-engineered, several I've tried don't seem to handshake properly. I
tried two back-to-back to run a local pppd link and it failed (haven't had
time to debug that one)

IMO there's no substitute for a real COM port.

> (not sure why, but chats tx/rx are for all calls in the pas 216 days, 
> not just this one).  This is in the past 4hours.  Perhaps with this 
> one, I am just better off telling it not to try v.90.

A pair of analogue modems will never negotiate v90, as for this one end has
to be digitally connected (typically T1/E1 trunk, although in theory you
might be able to find a modem which is physically connected as ISDN BRI but
which supports v90 analogue modulation)

The best you'll get is v34bis (33.6K)

Regards,

Brian.


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