EF JOHNSON 5100 ES II, Руководство по эксплуатации, Страница: 43 / 144

December 2006 5100 ES Model II/III Portable Radio Operating Manual 3-13
General Operation
3.9.1 Conventional Mode
This is a non-trunked operating mode which accesses independent radio channels. There is
no automatic access to several channels. Selecting a conventional channel selects a
transmit and receive frequency and other channel parameters such as squelch control
coding.
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
which is sent over the air as complex tones. 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.
3.9.2 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. Enhanced SMARTNET/SmartZone features include
roaming (SmartZone only), telephone, private, and emergency calls, Call Alert
™
, and
messaging. Either analog or digital signaling may be used (digital is optional).
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.