Operating instructions

ES Series Models II/III Portable Radio Operating Manual 11-7
Secure Communication (Encryption)
11.3.2 Analog Receive Mode Options
The following receive options can be programmed with conventional operation. With
SMARTNET/SmartZone and P25 Trunked operation, encrypted calls are received if the
proper key is programmed.
No Autodetect - Only signals coded like the transmit signals are received.
Proper Key Autodetect - (Analog Channels) When this feature is disabled and a
message is received with the wrong key, the audio unmutes and garbled (encrypted)
audio is heard. However, if this occurs with this feature enabled, the audio remains
muted.
11.3.3 Talkgroup Encryption Override
Conventional digital (P25), Smartnet/Smartzone and P25 Trunking encryption strapping is
programmed on a “per talkgroup” basis. However conventional digital and P25 trunking
talkgroup encryption strapping can be overridden on a “per channel” basis.Therefore, if
desired on Conventional Digital and P25 Trunking channels, encryption can be
programmed differently for each channel. Conventional analog channel encryption is
always programmed on a per-channel basis.
11.4 Over-The-Air Rekeying (OTAR)
Over-The Air-Rekeying (OTAR) is the process of sending encryption keys and related key
management messages over-the-air to specific radios. The advantage of OTAR is that it
allows these keys to be quickly and conveniently updated when necessary. It is no longer
necessary to periodically travel to the radio location or bring the radio into a maintenance
facility to load new keys.
The actual OTAR rekeying functions are performed by a Key Management Facility
(KMF) that sends Key Management Messages (KMM) to the radios. These messages are
themselves encrypted using an encryption key. Radios must be OTAR-compatible and
programmed for OTAR for this type of rekeying to occur.
Note The RSI is enabled in the KMF and must be assigned to the radio by programming.
OTAR is available only on P25 conventional and trunked channels, and only to program
DES-OFB and AES keys. It is not used on SMARTNET/SmartZone channels or to load
DES keys.