SmartTrunk Systems SmarTrunk II, Обзор системы, Страница: 6 / 57

System Overview
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Figure 1 - Which kind of line would you prefer to stand in?
A. B.
Queues Clerks Single Queue Clerks
The primary advantages of any trunked radio system can be
summarized as follows:
¨
Automatic selection of a clear channel: In a conventional radio
system, the user may only have access to a single channel. By FCC
regulation, if the user wishes to make a call, he must first monitor the
channel to make sure it’s clear. If the channel is busy, the user must
continue to monitor the channel until the co-channel user has
terminated the conversation. By contrast, in a trunked system the
channel selection is automatic. When the user initiates a call, the
trunking system electronically “monitors” each channel and selects one
clear (unused) channel from many possible channels.
¨
Channel Privacy: In a conventional system, other co-channel users
can easily eavesdrop on conversations. In fact, channel monitoring is
required by the FCC when initiating a call, as described above. In a
trunked system, other system users cannot listen in on other
conversations. A radio can only join a conversation when directed by
the trunking controller.
¨
Channel Exclusivity: In a conventional system, discourteous co-
channel users can “jump” on a channel in the middle of another
conversation, thereby interrupting the call in progress. In a trunked
system, once a channel is selected, it becomes exclusive for the
duration of the transmission. Other users cannot interrupt or interfere
with the call.
¨
Selective Calling: In most conventional radio systems, selective
calling is an expensive add-on option or may not be available at all. On
the other hand, some trunked radio systems provide extensive
selective calling capabilities as a standard feature. This means that
users can selectively call different groups or individuals in the system.
Each user is typically assigned a unique individual ID code and one or
more group ID codes. These codes can be dialed by other users in the
system to select only the specific groups or individuals with whom they
wish to communicate.
The Trunking Advantage
The advantages of trunking can be illustrated by a very simple
example. Most of us are familiar with problem of standing in line for a
bank teller or at a ticket window, as illustrated in Figure 1 below.
Queuing analysis shows that more people (customers) can be handled
with the same level of service when all servers (channels) are available
to all customers.