Help! (Computer-Modem Communication)

This is section 3 of a step-by-step trouble-shooter for those whose modem will not connect to their Internet Service Provider [ISP]. These sections should help you to identify why the modem will not connect, & perhaps to fix it.
Contents
The troubleshooter was originally written for users of the Windows® 95/98 operating system. This section can be used with any OS.

The first two sections have reviewed a list of known problems & then given us our first little successes - there is a good hardware connection between telephone socket & telephone through the modem, & we know that the modem is capable of receiving a dial tone. So far so good. This section is going to check that there is a working communication between the computer & modem.

Windows® 95/98 shields it's users from details that early modem users - and modern users of operating systems such as Linux - were (or are) stuck with. To give a flavour of this, immediately before my Motorola Soft modem connects the computer automatically sends two init strings to the modem:
    AT&F&D2&C1V1S0=0E0*bo4*ba4+a8e=1,1
    ATS7=60\T0M1\N7%C1\Q3*LS1X4
The point of this is that this was pre-programmed for me by the manufacturer & installed in place when the modem was installed in the computer. This is known as ease-of-use.

In a similar ease-of-use fashion, win95/98 has a very useful diagnostic built into the Control Panel modems utility which will both check the computer-to-modem connection & also produce some very useful info. Unfortunately this diagnostic is not available for other, less user-friendly OS's, such as Linux, winNT or win2000.

Checking Computer-to-Modem Communication
So What's the Result?

Oh Dear, Errors...
Well, at least the source of the problem has been found (always look on the bright side of life).

Essentially the absence of responses is indicating a Modem driver failure, & possibly a Modem hardware failure. Win95/98 users can investigate Device Manager (a tab on the System Properties applet in Control Panel), though this result is indicating that the modem needs to be completely uninstalled, then reinstalled in the computer.

It is almost impossible to give specific advice on uninstalling/reinstalling a modem - there are too many modem models, and too many computer systems, each with their own wrinkles - but a little general advice follows for win95/98 users:

Broadly, a modem needs a Com port which is it's own private preserve (no other devices occupying or using that port), with a private interrupt and address (resources) to match. Before the days of Plug'n'Play (PnP) these needed to be manually assigned with ISA devices, but are supposed to be automatic with PnP ISA or PCI devices.

Good luck!