When set to True, the TAPI modem dialer will add appropriate dialing prefixes to the number you are dialing, based on the current values of ModemAreaCode, ModemCountryName, and ModemLocation. When set to False, the modem dialer will dial the phone number exactly as specified by ModemPhoneNumber. Changing this value is equivalent to changing the "Use Country code and Area code" setting in the Connection Settings dialog box. The default value is True. This value cannot be changed if the connection is open.

expression.ModemUseDialingRules As Boolean