EDACS Fleetmap

EDACS Fleet mapping

Establishing a fleet map structure dictates the max number of agency and fleet calls which can be assigned. Within the fleet map structure, the more agencies that are setup, the more agency calls that can be assigned. The same is true for fleet calls. To enhance each agencies flexibility, you can have different fleet and subfleet structures for each agency to suit specific radio communications requirements

A group call is addresses using a Group ID (GID). The GID is composed of 11 bits to define a total of 2048 max groups. The fleet map is structures for each agency to suit their specific requirements.

• Maximum of 5 bits to be used for agencies
• Minimum of 1 bit to be used for fleets
• Minimum of 2 bits to be used for subfleets

Some examples of the possible fleetmaps are shown below (similar to Motorola Fleetmaps)

Agencies 	Fleets 	Subfleets
--------------------------------
2 	        32 	32
2 	        16 	64
2 	        8 	128
2 	        4 	256
4 	        32 	16
8 	        8 	32
8 	        16 	16
16 	        16 	8

The most common fleet map used by EDACS systems is 8 (3 bits) agencies, 16 (4 bits) fleets and 16 (4 bits) subfleets. If we take a couple of examples of group calls, you can easily see how simple the fleet structure really is.

Using a 3/4/4 structure, we can now partition the 11 bit Group ID (GID) as follows:

_ _ _ / _ _ _ / _ _ _ _

Agency Fleet Subfleet

Binary examples are shown below:

Agency 1, Fleet 1, Subfleet 1 (GID 273 Decimal)

0 0 1 / 0 0 0 1 / 0 0 0 1

Agency 1, Fleet 1, Subfleet 15 (GID 287 Decimal)

0 0 1 / 0 0 0 1 / 1 1 1 1

A group call for Agency 1, Fleet 1, Subfleet 0 (GID 272) is a Fleet group call. All subfleets in Agency 1, Fleet 1 will respond to the call. A binary representation is as follows:

0 0 1 / 0 0 0 1 / 0 0 0 0

When an EDACS radio sees the fleet call assignment (GID 272), it immediately associates Subfleet 0 as being a Fleet call for Agency 1, Fleet 1. If the radio's channel selector is on a subfleet within Agency 1, Fleet 1, the radio hears the call.

A group call for Agency 1, Fleet 0, Subfleet 0 (GID 256) represents an Agency Group call. All fleets and subfleets in Agency 1 will respond to the call. A binary representation is as follows:

0 0 1 / 0 0 0 0 / 0 0 0 0

When the radio sees the Fleet call assignment (GID 256), it will immediately associate Fleet 0, Subfleet 0 as being an Agency call for Agency 1. If the radio's channel know is on a subfleet within Agency 1, the radio will automatically hear the call on GID 256.

This type of fleet mapping ensures Agency Fleet calls under failure mode of operation (such if the Site Controller were to fail)