Windows XP Fax Facility: the appropriate UK Telephone Number forma

Dear All,
I have a Dell laptop, with Windows XP Professional. I am trying to
send a fax via Windows own fax facility (ie not using a fax machine);
however, it says there is not fax tone on the other side; ie it fails.
I read in Microsoft's article (
http://www.microsoft.com/windowsxp/u...october21.mspx
), that:
"Very Important: Telephone numbers must be in the canonical form in
which a U.S. number would appear as +1 (626) 555-1212. If you use even
a slightly different form such as (626) 555-1212 or 1-626-555-1212,
the dialing rules won't be applied and the fax transmission will
fail."
Does anybody know what the proper format of a UK tel no is? I follow
the above rule; but windows does not accept the sign of + and it does
not accept any variation of the above format.

Kind Regards,


Reza