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APCO P25 MODE OPERATION
n
OTAR function
P25 Over-The-Air-Rekeying (OTAR) function allows the Key
Management Facility (KMF) to change the encryption keys in
a transceiver remotely, (“over the air”) to protect the secure
communications.
Moreover, several OTAR commands are used to perform the
following operations.
From KMF to transceiver:
• Change Active Keyset
• Change Group RSI
• Radio Check
- The transceiver automatically responds to any command.
From transceiver to KMF:
• Registration to the OTAR system
• Deregistration from the OTAR system
• Rekeying
- When the channel in which the OTAR function is enabled
is selected, the transceiver automatically attempts registra-
tion to the OTAR system by transmitting a Key Management
Message (KMM) to KMF.
Various other commands are exchanged between KMF and a
transceiver, other than above.
Not available on Non-display types.
D
Registration to the OTAR system
➥
Push
[Zone], then push [CH Up] or [CH Down], or rotate
[CH Up/Down], to select a channel in which the OTAR
function is enabled.
After selecting the channel, the transceiver automatically
attempts registration to the OTAR system by transmitting a
KMM ‘Registration’ command to KMF.
NOTE: There are 2 types of KMM— Standard and Packet.
If the preset KMM type is not matched to the system to
which the transceiver attempts to register with, the regis-
tration attempt may fail. In that case, the transceiver’s KMM
type should be changed to another type.
D
Deregistration from the OTAR system
➥
Push
[CH Up] or [CH Down], or rotate [CH Up/Down],
to select another channel to exit the channel in which the
OTAR function is enabled.
After exiting the channel, the transceiver automatically
attempts deregistration from the OTAR system by trans-
mitting a KMM ‘Deregistration’ command to KMF.
