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Windows 95 > Communication Tips


Increase Modem Speed in Windows 95

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In Windows 95, your modem may seem to work fine, but the true fact is, the baud rate for you COM Port doesn't allow you to reach top-speed. To improve your port's speed:

  1. Click Start, Select Settings > Control Panel, open System
  2. Click the Device Manager tab, and click on the "+" sign next to Ports (COM & LPT)
  3. Select the port your modem uses, click Properties, then click the Port Settings tab, and set the Bits per second to 115200 bps, that way you won't have a sort of filter on the Port.

    115200 bps is the maximum setting for a "Standard" COM port. If you encounter problems, try setting this value lower. With System Monitor you can check if there are any problems. System Monitor (sysmon.exe) can be found on the CD-ROM version of Windows 95, or can be downloaded from Microsoft [55.5 KB]

    (If you are not sure which COM port your modem uses, click on the "+" sign next to the Modem Icon in Control Panel and select your Modem. Click on Properties and choose the Modem Tab. Here you will see the COM port used by your modem)

  4. For most modems you should use Hardware in the Flow control drop-down box.

For for more information, visit the HelpWithWindows Web Site. Here you'll find info on the MaxMTU fix, and other settings to increase your comm's speed.

It is not widely known, but the serial ports on motherboards and add-in cards that use some specific I/O controllers will support operation at speeds greater than 115200 bps:

  • ALI:
    M1543(Aladdin V south bridge)
    Serial ports provided by these chips will run at 230400 and 460800 bps.
  • NS:
    PC87308
    PC87307 / 87317
    PC97307 / 97317
    PC87309
    PC87338
    Serial ports provided by these chips will run at 230400 / 460800 / 921600 bps.
  • SMC:
    37C665IR / 666IR
    37C669 / 669FR,37N769
    37B72x / 77x / 78x / 80x,37C67x / 68x / 93x / 93xAPM / 93xFR,37M60x / 61x,37N958FR
    Serial ports provided by these chips will run at 230400 and 460800 bps.
  • WinBond:
    W83877TF (TF only, A/F/AF not supported)
    W83977F /AF /TF / ATF
    Serial ports provided by these chips will run at 230400 / 460800 / 921600 bps.

All they need is the proper software to enable and program these high speed modes.

For Win95/98, getting greater than 115Kbps requires two parts:

  • Executing a small program at boot time to enable the high speed mode
  • An updated serial.vxd that knows how to program the high speed rate

The file SHS17.ZIP from http://hp.vector.co.jp/authors/VA004958/over115K/index_e.html provides all you need to determine if your serial ports are compatible and, if so, to take advantage of the high speed operation that these chips support.

June 13, 2003