[TrunkCom] Police: City of Bethlehem, PA. (?)

[Arthur-Bryan E. Phelps]

I know I have all their trunking frequencies.  They use a Motorola II system.
 I was hearing them 5x5 since I programmed my 780xlt months ago.  Last Friday,
I heard nothing. My son who is a Bethlehem Police Officer said they were told
to use "PB 2."  I'm not certain what that means, program bank, power bank???
 He has no clue.  He just uses the radio when needed.  Does anyone have anyone
have any theories or actual knowledge of what happenes when "PB 2" was pushed?