Dial this number from your computer: 1-847-262-6000.

Most communications programs offer the ability to dial from a "phone book." Alternately, you may send the following command to your modem: 
ATDT1-847-262-6000 

You'll be connected to the LineTest system, and asked if your system supports graphics. Press the 'Enter' key to proceed. 
You'll then be prompted for your first name.
Type in: line
Press the 'Enter' key.
Next, you'll be prompted for your last name.
Type in: test
Press the 'Enter' key again. 
The LineTest system will perform a series of diagnostics on your connection, and will inform you of its conclusion. This may take a minute or so. 

If you see: "This connection supports 56K* technology!" Congratulations -- you're in good company! 

Tech Alert!
At this point, if you press the 'Enter' key, you'll see the first of two screens of line statistics. Press the 'Enter' key again for the second screen. When you're done, type in the letter g, then press the 'Enter' key to disconnect. 

If you're not interested in this information, type in the letter g, then press the 'Enter' key to disconnect. Dial up your Internet connection again, and you're ready to step up to high-speed downloads from the Internet! 

If you see: "Your line does not support 56K technology."
Type in the letter g, then press the 'Enter' key to disconnect. 

Since line conditions can change from call to call, we recommend that you make several calls to LineTest to ensure an accurate diagnosis. If you have multiple phone lines available for use, we recommend that you try calling from each line. 

If you see: "56K is not currently possible on this connection, or is likely to be highly impaired." Type in the letter g, then press the 'Enter' key to disconnect. 

The most likely reason for this response is more than one analog-to-digital conversion in the connection to your provider. If multiple calls indicate that your line won't support 56K technology, keep in mind that telephone network configurations can change, so your chances of making high-speed connections may improve over time. 

If you see: "Cannot determine 56K capability, test must run in V.34 mode." Type in the letter g, then press the 'Enter' key to disconnect. 

You may get this response if you have excessive "noise" or static on your phone line. Since line conditions can change from call to call, we recommend you try again at another time.