I have had a responce on this through other channels that seems to point the problem at the long distance prefix being 0 and the extension numbers in question starting with 0.
Some informaition on this system.
DDIs, BT currently delivers 5 digits.
04200-04269
09070-09099
02730-02799
08780-08799
Country Code 44
Area code 20
International Prefix 00
Long Distance 0
External prefix 9
I do not understand why this should effect it as it is not an external call as no 9 has been dialled. I am also struggling with why the 00, 02 and 04 ranges work. I thought this may be related to the DDI ranges but then would expect numbers starting with 09 and 08 to work but they don't. :-/
Anyway my next question is if I get BT to increase the amount of digits they send to 6, will this solve the problem? or make things worse. as I currently have users with extensions 204,209,202 and 208. With the extra digit it would look like this.
204200-204269
209070-209099
202730-202799
208780-208799
Any other solutions which people have to transfer direct to voice mail with out using "dummy" extension numbers may help too.
Thanks again
Nathan