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Modem Properties/Settings

This little section gives brief details, with screen shots from win95/98, on the bewildering array of modem settings as part of Troubleshooting a troublesome modem.
Contents
Foreword (sounding off)
Modems contain a bewildering array of settings, all of which need to be correct to allow connection. Sensibly the manufacturers provide default settings to allow connection in the majority of cases. However if you look here you will see a connection made with my modem set to factory defaults. These defaults, however, were USA defaults (I live in the UK) & my model at that time would not connect to Freeserve if set to UK defaults. This was finally fixed many months later with an updated driver.

Obtaining a reliable connection, in the early days of modem communications, was one long nightmare. The computer hardware would communicate via a UART with a Comm Port which interfaced with the Modem controller which then communicated through a DSP and then a Line Codec with the DAA which allowed access onto the telephone line across and through another modem's DAA, Line Codec & DSP to it's controller. If any one part couldn't talk with the next part, then the whole chain snapped & somehow you had to work out where & why then fix it. And none of this includes getting the communication protocols correct, of which there are perhaps 5 different parameters - each of which needs to be right - or nothing will happen even if all the hardware is OK. Aaargh! (Excuse me while I go & get a cup of tea.)

Well, OK, that was the past. In these modern days all of that is gone & forgotten, right? Well, no, actually. Everything in the paragraph above still exists - it has simply got smaller, faster & costs less. It has also become much better understood, and the war of competing protocols has mostly vanished in the face of Time & the ITU. In addition, there has been some advance in putting an easy-to-use interface between the pudgy idiot known as a user & the technological marvel known as a modem (irony) - but not much (just look at what it takes to change the Country setting).

Modem Connection Properties (win95/98/Me/XP)
To open the dialog as at right:
    open My Computer
    open Control Panel
    (Me: click on Show more)
    (XP: switch to Classic View)
    open Modems
    (XP: open Phone & Modem)
    (XP: click on Modems tab)
    press Properties button
    press Connection tab
Connection Preferences
    If you successfully connect to the Internet DON'T TOUCH THESE!
Call Preferences
    Wait for dial tone... Do NOT remove the tick from this unless the modem has the wrong Country setting & it cannot be changed. The only situation in which it SHOULD be switched off is when the modem is behind a switchboard with a weird dial-tone. The dial-string to get an outside line should then be terminated with a "W" (no quotes) which achieves the same effect. Disconnect a call if idle.... If this is set to a low figure it is very easy whilst browsing the Web to find yourself suddenly disconnected for no apparent reason.

    For now take any ticks out of 'Only connect at this speed' (General page, 'Maximum speed), 'Distinctive Ring' or 'Forwarding'.

Modem Connection Properties

Advanced Connection Properties (win95/98)
Press the Advanced... button on the dialog above right (with XP it is a tab) to display the famous Extra Settings box as at right:

Use error control

    For best both Error Control & Compression want to be switched ON. There have been reports of non-connection fixed by clearing the error-control tick-box, but this indicates a defective firmware flash rather than a modem or hardware problem
Use flow control
    Don't touch this. If you have an external modem & it needs software control, get another cable (or computer & modem!) Internal modems always use Hardware flow control.
 Modem Advanced Connection Properties

Advanced Connection Properties (cont.)
(The Extra Settings box - win95/98)
A Windows 95/98 screen shot is above right.

Modulation Type

Extra Settings Append to log