Rockwell HCF Modem UART Fix

Because the Rockwell HCF modem is partly software-controlled, it emulates certain chips that are found on hardware-based modems. One such chip is the UART. Windows sometimes misinterprets the UART the HCF is emulating, causing side effects like disconnections. Follow these to steps to see if Windows is reporting the correct chip, and if necessary, correct the problem:

  • Click the Start Button, choose Settings, and select Control Panel.

  • Double-click the Modems icon, then click the Diagnostics tab on the "Modems Properties" window.

  • A Rockwell HCF 56K Data Fax PCI Modem (or something similar) should appear on the list. Click and highlight the COM port assigned to it (COM1, COM2, etc.), then click the More Info... button.

  • After several seconds, the "More Info..." window appears. About one-third of the way down, Windows lists the modem's UART chip. If the number contains "8250", you need the UART fix. Continue with the steps below.

  • CLick OK on the "More Info..." window, and click OK again on the "Modems Properties" window.

The System Properties window

The Rockwell HCF modem's Resources window

  • In the "Control Panel" window, double-click the System icon, then click the Device Manager tab on the "System Properties" window.

  • Double-click the Modem icon in the list of devices.

  • You should see a Rockwell HCF 56K Data Fax PCI Modem entry (or something similar). Double-click on it.

  • On the "Rockwell Properties" window, click the Resources tab.

  • Uncheck the box for Use automatic settings. For the Setting based on: option, change the current configuration (normaly Basic configuration 0000 to 0001. If 0000 is not the default configuration, make a note of the default, then change it to one of the other configurations (0000, 0001, 0002, etc.).

  • Click OK, then click Yes on the warning window. Restart the computer.

  • Perform Steps 6 through 11 again, making sure that Use automatic settings remains unchecked. Change the Basic Configuration from 0001 back to 0000, or back to the original configuration.

  • Click OK, then click Yes on the warning window. Restart the computer.

  • The UART problem should now be solved. To confirm this, follow steps 1 through 4 above, and confirm the UART number has now changed to "16550". If it has not, begin with step 6 and try the proedure again.