Infinite Ukek Retention; Hear Clear - Motorola APX 4000 User Manual

68012004058-HV
Chapter 7 : Advanced Features
b. or to the desired encryption key or use the keypad to enter the number of the
desired key.
c. Press the Menu Select button directly below Optn .
The display shows the available key erase options.
d. or to the required option and press the Menu Select button directly below Sel .
e. Select Erase all keys? or Erase single key? by pressing the Menu Select button
below Yes to erase the encryption key(s) in the radio.
You can return to the previous screen by pressing the Menu Select button below No.
• Erasing the single key in radios with the single-key option and erasing all keys in radios with
the multikey option by using the preprogrammed Top Side (Select) button and Top (Orange)
button:
a. Press and hold the Top Side (Select) button.
b. While holding Top Side (Select) button down, press the Top (Orange) button.
The display shows Please wait. When all the encryption keys have been erased, the
display shows All keys erased.
NOTE: Do not press the Top (Orange) button before pressing the Top Side (Select)
button, unless you are in an emergency situation as this sends an emergency alarm.
7.16.3.6

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 programmed by a qualified radio technician. For more information,
contact your system administrator.
7.16.3.7

Hear Clear

Hear-Clear is a noise reduction system that 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.
The Random FM Noise Canceller operates only in receive mode.
NOTE: This feature must be programmed by a qualified radio technician. For more information,
contact your system administrator.
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