On Mon, 30 Jan 2006 07:58:56 +1100, Franc Zabkar
On Sat, 28 Jan 2006 18:18:11 +0200, "cquirke (MVP Windows shell/user)"

The client and server modems will speedshift downwards and
upwards as line conditions change.

Yep - that's why I like download speeds as a better guide, though
there are all sorts of variables there too. A fave trick was to
connect at high speed (to look good in the log) and then almost
immediately kick down to a speed that actually works.

The other worry is that he may have an elderly PCI system (say, a
486DX2-66 or Pentium-133) with a modern "soft" modem, and the
processing overhead of these "soft" modems can give problems that look
a bit like serial port overruns... may even present as such.

In fact there are three types of internal modem, "soft",
controllerless, and "hard" (controller based). Softmodems have a DAA
(telephone line interface), controllerless modems have a DAA and DSP
(digital signal processor), and "hard" modems have a DAA, DSP, and
controller.

DSP are highly CPU intensive, so a softmodem (which emulates the DSP
in software) may impact noticeably on CPU performance.

What they all have in common is a dependence on "drivers" (code, not
just an .INF of AT language) and no serial interface, so they can't be
troubleshot from DOS. You live and die by Windows drivers, and we all
know how flaky those can be... so they aren't fun to troubleshoot.

I prefer to avoid any sort of "soft" modem (but especially ones with
no DSP) on PCs slower than 500MHz or so. For field and
troubleshooting work, I prefer to use an extrnal serial port modem.



---------- ----- ---- --- -- - - - -
Don't pay malware vendors - boycott Sony
---------- ----- ---- --- -- - - - -