Phil,
I think the problem is with windows modem Dialing Rules.
If you have XP go to help type "area code rules" (in W2K is probably the
same).
Don't forget to check the box "Include the area code"
Here is a copy of the text:
To specify area code rules
1.. Open Phone and Modem Options in Control Panel.
2.. On the Dialing Rules tab, click the location to modify, and then click
Edit.
To create a new location, click New.
3.. Click the Area Code Rules tab.
4.. To add a new area code rule, click New.
To edit an existing rule, click the rule and then click Edit.
5.. In Area code, enter the area or city code.
6.. In Prefixes, select one of the following:
a.. To apply the rule to all prefixes in the area code, select the
Include all the prefixes within this area code check box.
b.. To apply the rule to specific prefixes, select the Include only the
prefixes in the list below check box, click Add, enter one or more prefix,
and then click OK.
7.. In Rules, select one or both of the following:
a.. To dial a number before the phone numbers that contain these
prefixes, select the Dial check box, and then type the digits to dial.
b.. To dial the area code before the phone number, select the Include
the area code check box.
Notes
a.. To open a Control Panel item, click Start, click Control Panel, and
then click the appropriate icon.