MM23772, Rev. F
72
9.19.3.1 Display the Currently Used Cryptographic Key Number
To Display the Currently Used Cryptographic Key Number for either the system encryption key (for
special call such as individual, phone, all, agency or fleet) or the group/channel key (for group or
conventional calls), perform the following procedure:
1. Press the button.
2. Use the or button to select "DISP KEY."
3. Then use the or button to toggle between displaying the system key (Figure 9-8) or the
group/channel key (Figure 9-9).
Figure 9-8: System Encryption Key Display
Figure 9-9: Group/Channel Encryption Key Display
9.19.3.2 Key Zero
All cryptographic keys can be zeroed (erased from radio memory) by pressing the button and while
still pressing this button, press and hold the button. Press both buttons for 2 seconds. A series of beeps
will begin at the start of the 2 second period and then switch to a solid tone after the keys have been
zeroed. The display will indicate KEY ZERO.
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.
9.19.4 Private Operation (P7200 Only)
9.19.4.1 Receive 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 is 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.