Method for providing limited secure services in secure trunking communication systems

In a secure trunking communication system that includes a central controller, a plurality of communication units, a limited number of broadcast units that transceive a limited number of communication resources, at least one console, and a limited number of console interface units that are operably coupled to the limited number of broadcast units, the at least one console, and the central controller, a method for the central controller to provide limited secure services when the central controller is not operably coupled to the limited number of console interface units, the method comprises the steps of:

• a) determining, by the central controller, that the central controller is not operably coupled to the limited number of console interface units;
• b) transmitting, by the central controller, a limited secure service message to the plurality of communication units;
• c) determining, by the central controller, that the central controller is once again operably coupled to the limited number of console interface units;
• and
• d) when the central controller is once again operably coupled to the limited number of console interface units, transmitting, by the central controller, a full secure service message to the plurality of communication units.

In a secure trunking communication system that includes a central controller, a plurality of communication units, a limited number of broadcast units that transceive a limited number of communication resources, at least one console, and a limited number of console interface units that are operably coupled to the limited number of broadcast units, the at least one console, and the central controller, a method for the limited number of console interface units to provide limited secure services when the central controller is not operably coupled to the limited number of console interface units, the method comprises the steps of:

• a) determining, by the limited number of console interface units, that the central controller is not operably coupled to the limited number of console interface units;
• b) loading, within each of the limited number of console interface units, at least one limited service key into a console interface unit encryption/decryption device;
• and
• c) utilizing the at least one limited service key by the limited number of console interface units until the central controller is operably coupled to the limited number of console interface units.

In a secure trunking communication system that includes a central controller, a plurality of communication units, a limited number of broadcast units that transceive a limited number of communication resources, at least one console, and a limited number of console interface units that are operably coupled to the limited number of broadcast units, the at least one console, and the central controller, a method for a communication unit of the plurality of communication units to provide limited secure services when the central controller is not operably coupled to the limited number of console interface units, the method comprises the steps of:

• a) receiving, by the communication unit, a limited secure service message;
• b) loading, by the communication unit, at least one limited service key into a communication unit encryption/decryption device;
• and
• c) utilizing, by the communication unit, the at least one limited service key until a full secure service message is received.

In a secure trunking communication system that includes a central controller, a plurality of communication units, a limited number of broadcast units that transceive a limited number of communication resources, at least one console, and a limited number of console interface units that are operably coupled to the limited number of broadcast units, the central controller, and the at least one console, a method for providing failsoft services when the central controller is inoperable, the method comprises the steps of:

• a) determining, by the limited number of broadcast units and the plurality of communication units, that the central controller is not operable;
• b) transmitting, by each of the limited number of broadcast units to a respective console interface unit of the limited number of console interface units, a failsoft service message;
• c) upon receiving the failsoft service message, loading, within each of the respective console interface units, at least one failsoft key into a console interface unit encryption/decryption device;
• d) loading, by each of the plurality of communication units, the at least one failsoft key into a communication unit encryption/decryption device;
• and
• e) utilizing the at least one failsoft key by the plurality of communication units and the limited number of console interface units until the central controller is operable.

In a secure trunking communication system that includes a central controller, a plurality of communication units, a limited number of broadcast units that transceive a limited number of communication resources, at least one console, and a limited number of console interface units that are operably coupled to the limited number of broadcast units, the central controller, and the at least one console, a method for the limited number of console interface units to provide failsoft services when the central controller is inoperable, the method comprises the steps of:

• a) receiving, by each of the limited number of console interface units, a failsoft service message;
• b) loading, within each of the limited number of console interface units, at least one failsoft key into a console interface unit encryption/decryption device;
• and
• c) utilizing the at least one failsoft key by the limited number of console interface units until the central controller is operable.

In a secure trunking communication system that includes a central controller, a plurality of communication units, a limited number of broadcast units that transceive a limited number of communication resources, at least one console, and a limited number of console interface units that are operably coupled to the limited number of broadcast units, the central controller, and the at least one console, a method for a communication unit of the plurality of communication units to provide failsoft services when the central controller is inoperable, the method comprises the steps of:

• a) determining, by the communication unit, that the central controller is not operable;
• b) loading, by the communication unit, at least one failsoft key into a communication unit encryption/decryption device;
• and
• c) utilizing the at least one failsoft key by the communication unit until the central controller is operable.