Beyond the Basics
tracking Motorola systems
There are really two types of Motorola trunking systems. These are usually referred to as Type I and Type II systems. Type I only occurs on some 800 MHz systems. All VHF and UHF trunking systems use Type II. One important distinction between these two systems is the amount of data transmitted by each radio when its push-to-talk button (PTT) is pressed. Every radio in a trunked system is assigned a unique ID so the central site computer can identify it when it’s used. Both Type I and Type II systems place radios (or radio users) into groups, called talk groups, and these talk groups are also assigned unique IDs. Some radios have access to only one talk group, while others have access to many talk groups. The talk group(s) each radio can access is called the radio’s affiliation(s). In a Type II system, when someone uses their radio, only the radio ID is transmitted when PTT is pressed, whereas in a Type I system the radio ID and its current affiliation are both transmitted when PTT is pressed.
Why the difference? Type II systems are slightly more advanced because the central computer maintains a database which is used to determine each radio’s affiliation(s).
Changes to a Type II system are easier than Type I because the system manager only needs to update the database instead of reprogramming individual radios.
Another difference between the systems is that Type I systems are arranged in a fleet-subfleet hierarchy. For example, it is possible for a city using a Type I system to designate 4 fleets, each with 8 subfleets. Their fleets might be the police department, the fire department, utilities, and administration. The police may decide to further divide their fleet into subfleets such as dispatch, tactical operations, detectives, north, south, east and west side patrols, and supervisors. All the available police radios would then be assigned to one of the police subfleets. Determining the
