User's Manual

GENERAL OPERATION
17
Revised August 2002
Part No. 001-5300-007CD-NR
the radio. There is a maximum of 16 keys that can be
loaded into the radio at one time.
NOTE: There is a security feature that automatically
erases the encryption keys when the bottom cover is
removed. This function is performed by a push button
switch S1 on the logic board.
As stated in the above “NOTE”, the transceiver
must be connected to an unswitched power source to
preserve the encryption keys in memory. However,
there is a storage capacitor (C173, 0.22 µF) which
maintains the 5-volt supply (and the encryption keys)
for a minimum of approximately 8 hours if power is
temporarily lost.
If an attempt is made to transmit a secure
message without loading the corresponding key,
“KEYFAIL” is displayed. The message must then be
transmitted in the clear mode (this is possible only if
the channel is strapped to “switchable” as described
below) or the key must be loaded.
SecureNet Key Selection
NOTE: This feature is available on conventional
channels only.
When multiple hardware keys are programmed
(see preceding information), the Hardware Key Select
option switch can be programmed to allow selection of
another key for the channel. This feature permanently
selects another key for the channel (cycling power or
selecting a different channel does not reselect the orig-
inal key). Therefore, to switch back to the original key,
it must be manually reselected. Proceed as follows to
select a key:
1. Press the Hardware Key Select switch and HWKEY
x is displayed. The “x” indicates the current key
selection from 0-15.
2. Rotate the Select switch to display the desired key
and then press the Select switch to select it. Press the
Hardware Key Select switch again to return the
display to normal operation.
3.18.6 CLEAR/SECURE STRAPPING
Transmissions on an analog channel are in the
clear mode if the channel has been strapped to the
clear mode by programming, and in the SecureNet
mode if it has been strapped (fixed) to SecureNet. If
the channel has been strapped to “switched”, the mode
is selected by the Clear/Secure option switch. When a
message is received or transmitted in the secure mode,
is displayed.
If the channel has been strapped “Clear” and the
option button selects the “Secure” mode on power up
and a transmission is attempted, “Clear Only” is
displayed and transmitting is disabled. Conversely, if
the channel is strapped “Secure” and the option button
selects the “Clear” mode on power up and a transmis-
sion is attempted, “Secure Only” is displayed and the
transmitter is disabled.
3.18.7 460 SCRAMBLING
The 460 Scrambling protocol is a proprietary
Transcrypt protocol that is compatible with the stand-
alone scrambling option from Transcrypt. The 460
type of scrambling is no longer available with 5300
transceivers.
3.18.8 TRANSMIT MODE OPTIONS
The following transmit options are available
when SecureNet encryption is selected:
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 3.16), 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. When the clear mode is selected by this
switch, “CLEAR” is flashed, and when the secure
mode is selected, “SECURE” is flashed.
3.18.9 RECEIVE MODE OPTIONS
With the SecureNet protocol, the following
receive options can be programmed:
No Autodetect - Only signals coded like the transmit
signals are received.