These frequencies are legacy channels from the old VHF Hi and lowband systems and are used for out of county unit interop.  All legacy channels are patched to talkgroups on the trunked system.  VCall/VTac, UCall/UTac, and 8Call/8Tac interop channels are also in use and are patched to corresponding talkgroups on the trunked system. VLAW31 (old PD National) is also patched into the trunked system.  Nationwide interop channels are found here: http://www.radioreference.com/apps/db/?aid=7742

Typically, VTAC channels are used to patch in Schuylkill County units that do not have system radios. UTAC channels are used to patch in Lebanon and Lancaster County units that do not have system radios. 8TAC channels are used to patch in Chester and Montgomery county units that do not have system radios. However, any of the conventional interop channels may be used to patch in any unit needing to talk on the Berks system depending on what the end user has available.