This tweak can be easily applied using WinGuides Tweak Manager. Download a free trial now!

Windows is normally limited to a default maximum speed of 115,200 bps for serial communications. By using compression and high-speed UARTS modern modems may reach this limit and not be allowed to operate at full speed. This tweak allows Windows to communicate with speeds of 230400, 460800 and 921600 bps.

Open your registry and find the key below. If you have more than one modem there will be multiple sub-keys 0000, 0001, 0002...000x representing each modem. Check under each sub-key until you find the modem you want to speed-up then continue with the step below.

Make a backup of "Properties" value before it is modified. Then double-click on "Properties" and notice that the 51st, 52nd, 53rd and 54th digits will currently show "C2 01" or "84 03". Highlight these digits and then change them to "10 0e", do not change any other digits.

Click OK and exit the registry editor.

Now if you open "Control Panel -> Modems -> Your Modem -> Properties -> General" three new Maximum speed settings will be available: 230400, 460800 and 921600. Select the required speed and test with you modem to make sure it is compatible with the higher speed.

Note: Once enabled open Control Panel -> Modems -> Your Modem -> Properties -> General and set the required maximum speed.

Note: Some older slower modems may not be able to operate at these speeds, if your modem experiences problems switch back to a lower speed.

		(Default)	REG_SZ	(value not set)
		Properties	REG_BINARY	c0,01,00,00,ff,00,00,00,ff,00,00,00...

	HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Class\Modem\0000

Disclaimer: Modifying the registry can cause serious problems that may require you to reinstall your operating system. We cannot guarantee that problems resulting from modifications to the registry can be solved. Use the information provided at your own risk.