Hi; I am in the process of planning a PBX/Voice mail system for a business with an ISDN phone system and somewhere on the order of 12 internal phones. The ISDN system appears to be a Primary Rate Interface, though this may be irrelevent because receptionists answer all inbound telephone calls before possibly transferring via the PBX, and most calls do not get transferred. Telephone use might be considered to be average to low among those with internal phones (most contact is done via face to face though occasional calls must be placed out). Any advice on capacity planning? How many lines should one plan on having available via the PBX in general? Any advice on calculating this? Additionally, the PBX is replacing an old system (80286-based) due to the fear that a failure of an ancient piece of hardware could take down their phone system. Are there any hidden gotcha's that people think I should be aware of? Best Wishes, Chris Travers Metatron Technology Consulting