It wasn't a
requirement that they all have ISPERN radios in the cars but it was close. Most agencies in Illinois did participate as they got free radios.
In the 60's and 70's the Illinois State Police managed federal LEAA and state grants to provide VHF mobile radios for any police agency that chose to participate. It was controlled by the ISPERN Governing Board that issued permissions and provided the radios. Installations were the responsibility of the local agencies.
The radios originally were 4-channel Motorola & GE 110 watt mobile radios of the era (Mocom, MastR) with F1 as ISPERN (154.680 at first, in 1976 it changed to 155.475). The rules were that you could put other channels in Channels 2,3,4 but not disable the Priority status hardwired to ISPERN/F1. They were not supposed to use them for primary dispatch channels, you had to provide your own radios for that. State issued ISPERN radios were equipped with red mics so officers would know they were using that radio.
If you provided your own VHF radios you could set them up your way but still needed to get permission to have ISPERN in your radios. The State Police held the license (KN3600) for the mobile radios on ISPERN. If your agency had VHF handhelds you could add ISPERN to them as well.
Participating police departments also had to have a base receiver on ISPERN but only a few select centers could actually have a transmitter. These were Chicago PD, Cook County and Lake County Sheriff and the couple dozen State Police posts.
Later on the ISPERN Board relaxed some of the restrictions and turned over official ownership of the radios to the agencies possessing them and stopped issuing the radios altogether. Agencies could then provide their own VHF radios and equip them with ISPERN.
Most agencies in the Chicago area that moved from VHF to T-Band would put their old VHF channel in the F2 slot of the ISPERN radios for car-to-car use and often the local PW channel in F3 for use at night. F4 was often the local fire channel but these layouts varied widely from town to town. Many agencies did defeat the F1 Priority by rewiring the switch even though it was not permitted.
There were operational rules for ISPERN regarding flash messages, pursuits and other interagency communications. Intra-agency operations were generally banned (You could not use ISPERN for routine dispatch if your main channel went out etc.).
Eventually, after IREACH (155.055) was established, the suggested channel plan for ISPERN owned and locally provided radios was:
- F1 ISPERN
- F2 Local Option (often the old VHF dispatch or PW channel)
- F3 IREACH
- F4 Local Option (Often the local fire channel)
IREACH was also set up with a Board and base stations were limited to those authorized by this board. More dispatch centers were allowed on IREACH due to the different operational guidelines. IREACH was intended for multi-disciplinary operations, including police, fire and other governmental and emergency agencies as well as 9-1-1 "Closest Unit" situations. My dispatch center was granted an authorization in order to provide regional service on it and because no one else in the area had stepped up for it.