E.F. Johnson Company 5300 ES Series, Руководство по эксплуатации

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March 2008 5300 ES Series Mobile Radio Operating Manual 3-7
General Operation
Conventional channels can be either standard (analog) or Project 25 (digital). With digital
operation, the DSP (Digital Signal Processor) converts the audio signal to digital data.
Another difference is that analog channels use Call Guard (CTCSS/DCS) squelch control
and Project 25 channels use a NAC (Network Access Code) and talk group ID codes.
With Project 25 operation, a NAC is transmitted and it must match the NAC programmed
in the base equipment and the radio(s) being called for communication to occur. In
addition, to receive standard group calls, the receiving radio must be programmed to
detect the transmitted talk group ID code.
With conventional operation, a busy channel condition is detected automatically if the
busy channel lockout (transmit disable on busy) feature is programmed. Otherwise, it must
be detected manually. An out-of-range condition is not indicated by special tones or
messages as with SMARTNET operation because there is no initial data exchange with
the repeater that allows this condition to be detected. Operating features unique to
conventional channels are described in Section 5.
3.7.2 SMARTNET / SmartZone Mode
This is a trunked operating mode in which automatic access is provided to several RF
channels. ID codes are used to select what radios are being called and what calls are
received. Monitoring is performed automatically and special messages and tones indicate
busy and out-of-range conditions.
SMARTNET and SmartZone operation and programming is very similar. Basically,
SMARTNET operation is limited to a single repeater site and SmartZone operation allows
automatic roaming between sites. SMARTNET/SmartZone features include roaming
(SmartZone only), telephone, private, and emergency calls, Call Alert
™
, and messaging.
Either analog or digital signaling may be used. Enhanced SMARTNET/SmartZone
features provide the same, plus gives you responses from the system. For example, if the
ID you are calling is turned OFF, the system will display “NOT AVAILABLE”.
When a SMARTNET or SmartZone channel is selected or the radio is powered up on one
of those channels, it searches for a control channel. Once a control channel is found, the
alias (name) of the selected channel is displayed and the radio attempts to register on the
radio system. If a control channel could not be found (because of an out of range condition
or the system ID is not correct, for example), “NO SYS” (early units) or “OUT RNGE”
(later units) is displayed and the radio continues to search for a control channel.
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 information and is used to make call requests. When the radio
is keyed, a channel grant request is sent through the control channel. The system then
informs the requesting radio what traffic channel to use, through the control channel. Once
the request is granted by the system, the radio moves to the designated traffic channel for
the actual talk group call. Once the transmission has ended, the radio returns to the control
channel.