Problems Using Microsoft Fax with RPI Modems

• Microsoft Windows 95

SYMPTOMS

When you try to send a fax with Microsoft Fax, the fax may not be sent completely or at all.

CAUSE

This problem can occur when you are using a modem that uses Rockwell Protocol Interface (RPI) compression at speeds greater than 9600 bps. The following modems are known to use RPI compression:

• Zoom 14.4 PC Model 110 (internal)
• Zoom 14.4 EX Model 160 (external)
• Some Best Data internal 1442F fax/modems

  To determine if your Best Data internal 1442F fax/modem is an RPI modem, follow these steps:

  1. In Control Panel, double-click Modems.

  2. Click the Diagnostics tab.

  3. Click the COM port the modem is using, and then click More Info.

  4. Check the results in the More Info box.

RESOLUTION

To resolve this problem, contact the modem's manufacturer to inquire about a possible firmware upgrade or software patch that corrects this problem in Windows 95.

If a firmware upgrade or software patch is not available, you may be able to work around the problem by configuring the modem to operate at a slower speed. To do so, follow these steps:

1. In Control Panel, double-click the Mail And Fax icon.

2. Click Microsoft Fax, and then click Properties.

3. On the Modem tab, click your modem, and then click Properties.

4. Click Advanced.

5. Click the Disable High Speed Transmission and Disable Error Correction Mode check boxes to select them, and then click OK.

6. Click OK until you return to Control Panel.

1. In Control Panel, double-click the Modems icon.

2. Click your modem, and then click Properties.

3. In the Maximum Speed box, click 9600.

4. Click OK or Close until you return to Control Panel.

MORE INFORMATION

Modems that use RPI compression require a special program to enable the modem's error correction and data compression capabilities. Some communications programs already include this functionality, and some modem manufacturers provide a patch that implements RPI compression in Windows and Windows for Workgroups version 3.1x. This functionality is not included with Microsoft Fax, and the patches that are currently available from some modem manufacturers are not compatible with Windows 95.

Because the error correction and data compression capabilities of the modem have not been enabled, the modem is not reliable when operating at higher speeds.