Fax Modem Registry Entries

In general, modem INFs do not need to have FAX entries. FAX entries are only used to override detected FAX settings.

The Microsoft Fax modem drivers and T.30 protocol engine use several registry key settings to control their behavior. These settings are determined the first time the fax software is run, using a combination of the following techniques:

• Querying the modem for capabilities.
• Querying the modem to get an ID, and then using this ID to look up an internal table.
• [New in Windows 95] Reading the Unimodem INF section for the particular modem installed. If an entry is present in the INF section, it overrides information obtained via the previous two methods.

It is important to note that over 95% of the modems tested by the Microsoft Fax group do not need any fax Unimodem entries in the INF file. The fax entries should only be specified to fix known incompatibilities with Windows 95 or NT-SUR fax.