E.F. Johnson 5100 SERIES Service Manual - page 19
OPERATION
2-8
September 2001
Part No. 001-5100-001
The control channel transmits and receives
system information to and from all radios registered on
the system. Therefore, once a control channel is found,
it is continuously monitored for incoming call infor-
mation and is used to make call requests. The radio
automatically changes to a traffic channel to place and
receive calls and then returns to the control channel
when the call is complete.
2.4.13 SECURE COMMUNICATION
This transceiver may be optionally equipped to
provide secure communication on some or all chan-
nels. This feature encrypts your voice so that it can be
understood only by someone using a transceiver
equipped with a similar encryption device and encryp-
tion codes.
When a secure call is received or transmitted,
“
Sec
” is indicated in the upper part of the display.
Secure communication can be programmed on a per
channel basis to operate in various ways. If equipped
with the Clear/Secure option switch and the current
channel is programmed to allow switch selection,
secure communication can be manually enabled and
disabled by that switch. Secure communication can be
programmed on a per channel basis to operate in
various ways. Refer to Sections 2.6.17 and 2.7.15 for
more information.
2.5 SCANNING
2.5.1 INTRODUCTION
Scanning cycles through a list of channels called
a “scan list”, checking each for messages. When a
message is detected that your transceiver is
programmed to receive, scanning stops and the
message is received. Shortly after the message is
complete, scanning resumes (unless it has been
disabled).
There are two basic scan modes: Standard and
Radio Wide. The Standard mode is unique to the type
of channel selected (conventional or SMARTNET/
SmartZone), and the Radio Wide mode is the same
regardless of the channel type selected. Only one of
these scan modes can be enabled at a time. Therefore,
if standard scanning is enabled while radio wide scan-
ning is occurring, radio wide scanning is automatically
disabled and vice versa. More information on these
modes follows.
2.5.2 STANDARD SCANNING
Standard scanning monitors only channels that
are the same type as that currently selected. There-
fore, if a conventional channel is selected, only
conventional channels are scanned, and if a
SMARTNET channel is selected, only SMARTNET
channels are scanned. Standard scanning is turned on
and off by the Scan option switch as follows. If this
switch is not programmed, standard scanning is not
available.
•
To turn standard scanning on, press the Scan option
switch. Scanning is enabled when the “
Scan
” icon
is indicated in the upper right corner of the front
panel display and “SCAN ON” is briefly displayed.
•
To turn scanning off, press the Scan option switch
again. The “
Scan
” icon is then no longer indicated
and “SCAN OFF” is briefly displayed.
•
If the zone or channel is changed while scanning is
selected, scanning continues on the same or a
different scan list (see scan list information which
follows).
2.5.3 RADIO WIDE SCANNING
Radio wide scanning monitors the channels in the
preprogrammed radio wide scan list (see Section
2.5.5). This list may contain up to 16 channels of any
type (conventional or SMARTNET/SmartZone)
assigned to any zone. Radio wide scanning is turned
on and off by the Radio Wide Scan option switch as
follows. If this switch is not programmed, radio wide
scanning is not available.
•
To turn radio wide scanning on, press the Radio
Wide Scan option switch. Scanning is enabled when
“
Scan
” is indicated in the upper right corner of the
front panel display and “SCAN ON” is briefly
displayed.
•
To turn radio wide scanning off, press the Radio
Wide Scan option switch again. The “
Scan
” icon is
then no longer indicated and “SCAN OFF” is briefly
displayed.