7.14.3.4
Requesting an Over-the-Air Rekey
Prerequisites:
Ensure that the Unique Key Encryption Key (UKEK) or Unique Shadow Key (USK) is
loaded into the radio with the Key Variable Loader (KVL) before the rekey request can be sent. Refer
to your local key management supervisor for more information.
Procedure:
1
Press and hold the preprogrammed
Rekey Request
button to send the rekey request.
If the rekey operation fails, a bad-key tone sounds and the display shows
RKY FAIL
.
NOTE:
The rekey operation failure indicates that your radio does not contain the UKEK
or USK.
7.14.3.5
MDC OTAR (Conventional Only)
This feature allows you to view or define the Motorola Data Communications (MDC) Over-the-
Air Rekeying (OTAR) features. It is applied only when operating in secure encrypted mode. In
addition to Rekey Requests, OTAR transmissions include Delayed Acknowledgments, and Power-up
Acknowledgments.
Some of the selected options require configuration at the Key Management Controller (KMC) site to
work properly.
NOTE:
This feature must be preprogrammed by a qualified radio technician. Contact your
system administrator for more information.
7.14.3.6
Infinite UKEK Retention
This feature enables Unique Key Encryption Key (UKEK) to be permanently stored in the radio even
when all the encryption keys are erased. Without this UKEK key, the radio cannot be rekeyed over the
air. The Infinite UKEK Retention settings can be different for each secure profile.
NOTE:
This feature must be preprogrammed by a qualified radio technician. Check with your
dealer or system administrator for more information.
7.14.3.7
Hear Clear
Hear-Clear is a noise reduction system which consists of Companding and Random FM Noise
Canceller.
Companding
Reduces the channel noise, such as OTA transmission that is predominantly present in UHF2 and
900 MHz channel with the following features.
Compressor
Reduces the background noise flow and the speech signal at transmitting radio.
Expander
Expands the speech while the noise flow remains the same at receiving radio.
Random FM Noise Canceller (Flutter Fighter)
Reduces the unwanted effects of random FM noise pulses caused by channel fading under high
Signal-to-Noise (S/N) conditions such as in a moving transportation. The fading effects, heard as
audio pops and clicks, are canceled without affecting the desired audio signal.
MN006727A01-AE
Chapter 7 : Advanced Features
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