~770 unknown phone numbers as of 8/1/99
Of these ~720 were charged for (others are virtual
numbers, e.g. secretarial roll-over etc.)
None of these phones had made a call out of SLAC in
last 12 months
PBX does not log calls made on site
Some of phones may be for emergencies (e.g. in
gallery, rings, tunnels)
When we go to new phone PBX, unknown phones
will be disconnected
Current contract ends in September 2002