20th July 2001
Dial-in ISP got you down? Literally? Maybe it's not their fault. Yeah, right! They are notorious for changing things without telling anyone beforehand -- particularly their paying customers. Nevertheless, sometimes it is indeed on your end, and you're left to troubleshoot the problem on your own (as ISPs often offer little assistance in these situations). Well, Windows can create a log file containing diagnostic information, which can then be used to determine if there are initialization errors or other problems with the communications hardware. The trick is finding the file! Depending on which version of Windows you have, it will have a differently formatted name: it might be 'ModemLog_LT Win Modem.txt' in Windows 2000 or 'Lucent Win Modem.txt' in Windows ME. Or, you could take the easy way and open the Modems Control Panel applet and select the modem with which you want to work. This will vary slightly, again, depending on which version of Windows you're using, but you should be able to find a "View Log" button associated with your modem's properties. There is also an "Append to Log" checkbox that will continue to log information without clearing the log at each initialization or system restart. Be sure to disable this checkbox when you've determined the problem, since the log file will continue to grow over time. At least you won't be in the dark!
With the logging enabled, you will be able to see all of the AT commands that are sent to your provider (and the responses that are received). These commands may seem cryptic, but they each mean something to the modem -- such as enabling specific communication options, changing the speaker volume, or perhaps loading the default settings from the modem's memory. Every modem is slightly different in the command sets that they support, but the basics of the AT command set are supported by nearly every modem available today. For instance, sending AT (attention) to the modem should result in "OK" being received in return; it ensures that the modem is still alive. This is akin to a PING command in TCP/IP. Consult the documentation for your specific modem to check for all of the available AT commands that you can send to your modem. Some ISPs will even recommend a general modem initialization strings to be used with their system, so check with them before you dig too deep. And ALWAYS backup!