E.F. Johnson 5100 SERIES Service Manual - page 28
OPERATION
2-17
September 2001
Part No. 001-5100-001
with the 460 Scrambler, a Clear/Secure option switch
may be programmed. Pressing this switch changes the
transmission mode for the selected channel and
momentarily displays either “CLEAR” or “SECURE”.
In the coded mode, transmissions are in scram-
bled voice on any 460-enabled channel and the mobile
receiving the call automatically responds in the scram-
bled mode because the receiver automatically switches
between the clear and coded modes.
Although 16 generic codes are loaded, only one is
active and all 460-enabled channels use this code. The
460 scrambling option also provides several other
signaling enhancements including Digital ID, Auto-
matic Status and Location Update, Individual and
Group ID calling, and Emergency.
Transmit Mode Options
Either the SecureNet or 460 protocol can be
selected, and then the following transmit options are
available for each:
Clear -
All calls are in the clear mode unless
responding to a secure call. If the response is then
made within the delay time (see Section 2.5.4), it
occurs in the secure mode.
Coded -
All calls are made in the selected secure
mode.
Switched -
The mode is selected by the Clear/Secure
switch. With 460 scrambling, if responding to a secure
call, the secure mode is automatically selected if the
response occurs within the delay time. When the clear
mode is selected by this switch, “CLEAR” is flashed,
and when the secure mode is selected, “SECURE” is
flashed.
Receive Mode Options
With 460 scrambling, clear and scrambled signals
are always autodetected. In addition, the user can
switch between the clear and secure mode at any time
using the Clear/Secure option switch. SecureNet
signals are unintelligible when 460 scrambling is used
and vice versa.
With the SecureNet protocol, the following
receive options can be programmed:
No Autodetect -
Only signals coded like the transmit
signals are received.
Secure Autodetect -
Both clear and SecureNet signals
are automatically detected. This mode is automati-
cally selected if the transmit mode is switch selectable.
Proper Key Autodetect -
An incoming Securenet call
is compared against all of the available keys
programmed into the radio. If a match is found, the
call is decrypted using matched key.
Project 25 (Digital) Channels
Project 25 digital channels use the DES-OFB
protocol. Using this protocol on digital channels does
not result in the degraded range that occurs with
analog channels. The same transmit mode options are
available as with the preceding analog operation. In
the receive mode, clear and secure messages are
always automatically detected.
2.7 SMARTNET/SMARTZONE FEATURES
2.7.1 INTRODUCTION
The following information describes features
unique to the SMARTNET and SmartZone operating
mode (see brief description in Section ). Refer to
Section 2.4 for information on features common to all
operating modes, and to Section 2.4.12 for information
on conventional mode features.
2.7.2 VIEWING UNIT ID
Each radio in a SMARTNET system is identified
with a six-digit system ID and Unit ID. To display
these IDs, make sure that a SMARTNET channel is
selected and then turn power off and then on again.
The system ID is briefly displayed as SYxxxxxx
followed by the Unit ID as EDxxxxxx.
2.7.3 STANDARD GROUP CALLS
Standard group calls are between you and another
mobile, group of mobiles, or a control station (a radio