Docster is correct.
Signal 2 in Wash. Co means the channel is closed except for the unit(s) on a specific incident.
(ie. dog track, foot/veh. pursuit, fight, code 3 cover etc etc)
On friday night, they had a Signal 2 on SO 1, SO 2, AND Common Law - for 3 seperate incidents. That was the first time I had heard THREE signal 2's at once !!!
So yea, I could see how they would be looking for what channel to dispatch any remaining units from.