E.F. Johnson Company Viking VM600 Operating Manual page 168

Secure Communication (Encryption)
Every time the radio goes to a data channel, the data channel icon will come ON, and stay
ON, until the radio leaves the data channel. The radio goes to the data channel to do P25-
data related tasks, such as data register, OTAR register, send/receive OTAR data, and
send/receive OTAP data.
You must have successfully data registered before you can successfully initiate an OTAR
session. The usual sequence when the radio is attempting to data register will be:
- The data channel icon comes ON.
- The data context icon comes ON (once we successfully data register).
- The data channel icon goes out (once the radio returns to a control channel), but the
data context icon stays ON.
- The Data Registration Server icon comes ON once successfully registered with the
DRS (Lightning Control Head only).
If the data context icon is not ON, you do not have an SNDCP context (i.e., you are not
data registered). If the data registration icon is not ON, you are not DRS registered
(Lightning Control Head only).
Once the radio has a data context, if it is configured for OTAR and has a UKEK, it will
attempt to OTAR register. Depending on timing, the radio may stay on the data channel
for a longer period of time (the second step above) while it OTAR registers, an action
which can kick off an OTAR update procedure. Eventually the radio will leave the data
channel. The radio will be told by the system when it should the data channel.
A sign that the radio has not successfully OTAR registered is that the radio's data context
icon will be ON, but the radio will periodically keep going back to the data channel (the
data channel icon will periodically come ON and then OFF). The number of times the
radio will attempt to OTAR register and the amount of time it will wait between events is
set by programming.
Draft 02 - Sep 1 2015
7-12 Viking Mobile Radio Operating Manual