We have a specially provided pstn connected to an fxo port on a UC320W. Because I cannot have more than one fxo trunk, I have provided this pstn as a shared fxo and thus each of the member handsets has a key to access it. This works. BUT the number of digits to be dialled as a number varies between 4 and 9 (it is a private network) and this doe snot work - instead the handset reports "service unavailable". Am I correct in assuming that because the site config (for normal BT lines - this is a UK install) states an STD code plus 6 digits, I can only dial 6 digits on this shared fxo?