Tyco Electronics P5400 manual Private Operation, Receiving an Encrypted Call

MM-012099-001, Rev. B

If the cryptographic key(s) are zeroed, one or more keys must be transferred from the Keyloader into the radio before private communications may continue.

8.18.4Private Operation

8.18.4.1 Receiving an Encrypted Call

When receiving, the radio automatically switches between clear or private operation. If the transmission

being received is an encrypted transmission, it will be decrypted, the icon will be displayed, the receiver will unsquelch, and the message will be heard in the speaker. For this to occur, the selected group or channel must be programmed for private operation and the correct cryptographic key must be loaded into the radio.

8.18.4.2 Transmitting an Encrypted Call

1.Select the desired group or channel.

2.Place the radio in Private Mode by pressing key; then follow the selection mode rules. On a

System radio, the key can be used to toggle the Private Mode ON/OFF. When Private Mode is enabled, the icon is displayed.

3.If the last state of the radio was Private Mode, the Private Mode will be enabled on power up. Also, the Private Mode will be enabled if forced operation has been programmed in the radio.

If a group or channel is not programmed for Private Mode operation, PVT DIS will be displayed if an attempt is made to enable private transmit mode. It is not possible to operate on this group/channel in Private Mode.

If the radio does not have the correct encryption key loaded, NO KEY# will be displayed and the call will not be transmitted.

4.Continue with standard transmission procedures. A Private Mode access tone will be heard when the PTT button is pressed.

8.18.4.3 Scanned Group Calls

Receiving a Scanned Group Call is the same as receiving a selected group call. During the scan hang time, if the radio was programmed for auto-select, it will transmit back in the same mode it received the call. For example, if a clear group is entered in the scan list, it will only receive clear calls. If the same group was available in private and entered in the scan list, it can receive clear and private calls, provided auto-select was programmed in the radio. The user can select transmitting on the scanned or selected group. If a group is entered in the scan list more than once and under different modes, (clear, digital, or private), then only the first occurrence of the group will be used.

Table 8-7: Transmit/Receive Mode Compatibility for Digital Voice Operation

GROUP/CHANNEL	CLEAR	DIGITAL	PRIVATE
PROGRAMMING
	RECEIVE	RECEIVE	RECEIVE
(TRANSMIT)
CLEAR	Yes	No	No
DIGITAL	Yes	Yes	No
PRIVATE	Yes	No	Yes*

*assumes the proper cryptographic key is loaded

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