General Traps to Avoid When Editing INF Files

Before you start editing a modem INF file, such as SMPDATA.INF, keep the following common modem INF file item formatting and content errors in mind:

• If using a word processor to edit the INF file, always remove any non-ASCII characters which could accidentally be appended to the end of the file. An INF must be pure ASCII.
• Within the [Strings] section, do not use the following characters in modem names: < > : " / \ | Using these characters will usually causes errors in installation or testing.
• Do not use a period (.) at the end of a modem name in the [Strings] section.
• Do not incorrectly apply an AT command or init to all modems. For example, a specific modem may require AT&F1 instead of AT&F, or a modem may use \Tn for inactivity timer instead of S30.
• Do not forget to use double percent sign (%%) or double quotation mark ("") in INF commands which use these symbols. For example, use %%C1 in an INF to enable compression not %C1. Likewise use ""H3 not "H3.
• Check the properties line of the INF for correct maximum DTE and DCE speed. You can usually determine maximum DTE by glancing at the MODEMDET.TXT file which Windows 95 generates when a new modem is installed. You can also determine max DTE and DCE by consulting manufacturer documentation or by trial and error with any communications program. Use the communications program to transmit init strings to the modem at various DTE speeds by trial and error to find the maximum DTE value.
• To find fixes for persistent errors, study other INF files provided with Windows 95 to see what might be missing. These are stored in the \WINDOWS\INF directory and are usually listed as MDM*.INF
• Two lines are generally added to the default MfgAddReg section to assist a modem in answering incoming calls. The lines below are used to make sure that the S0 register is forced to 0 since some modem Nvram settings may default to settings greater than 0 on power up. Note the placement of these two entries by studying other Windows 95 INFs.

HKR, Monitor, 1,, "ATS0=0<cr>"
HKR, Monitor, 2,, "None"