Northeast Tarrant County
From The RadioReference Wiki
As of 10/1/2010 the cities of Colleyville, Keller, and Southlake are sharing dispatch operations. For the police, here's what I've been able to figure out about unit numbers.
1##s Colleyville
2##s Southlake
3##s Keller, which also patrols Westlake
7## Southlake School Patrol
This is important to know, because they are all on C-PATRL1. C-PATRL2 sounds like it's going to be for records checking.