Improving Modem Throughput Speeds

Updated: August 31, 2007

Applies To: Windows Server 2008

If you consistently connect at slower speeds (24 Kbps or less for a 33.6 Kbps modem or less than 40 Kbps for a 56 Kbps modem), you can try the following:

  • Check that the correct model and make are listed for your modem in Phone and Modem Options in Control Panel. If your modem is not listed correctly, try following the steps in Install an unsupported modem to install the correct modem.

  • Check if the manufacturer has a new installation disk or .inf file available. Files can often be downloaded from a manufacturer's Web site.

  • For a 33.6 Kbps modem, make sure the Maximum Port Speed is set at 38.4 Kbps or higher (57.6 Kbps is recommended). For a 56 Kbps modem, make sure it is set at 115.2 Kbps. For more information, see Change the Maximum Modem Port Speed.

  • Make sure the modem is operating at the correct temperature. Most modems operate better if they do not get too hot or too cold. Do not block air flow by placing things on top, under, or around your modem or computer.

  • Try connecting to numbers that you know support a specific speed. This lets you know whether the problem is at your end or the other end.

  • Make sure a local number is actually a local call. Many ISPs forward local calls to a distant location to provide local calling service. This works well at 14.4 Kbps, but can degrade the signal and limit higher speeds.

  • If your phone line has a surge protector, try using your modem without it. Note, however, that doing so eliminates the protection provided to your equipment by the surge protector.

  • Have an expert check the telephone wiring between the telephone company connection and your computer. Faulty wiring, soldered connections, long connecting cables, inferior equipment (phones, fax machines, or even other modems) can all degrade the signal. To distinguish between wiring and line problems, check the voice quality, both while the local wiring is connected and on the telephone company line while disconnected from the local wiring. Many phone companies now connect their service with a modular plug, which consumers can disconnect to perform this check.

Additional Information

For additional information, see the following: