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Bosch Security Systems | 2011-02
2011-02 | Installation and User Instructions | 2 | Introduction en | 79
3.2.5 Timing
Most calls are broadcast immediately, but calls can be
time-shifted for broadcasting after completion of the
original call. This avoids acoustic feedback between the
microphone and nearby loudspeakers. A time-shifted
call can also be pre-monitored to check the content
before it is broadcast and optionally cancelled. This
feature is only available in combination with a call
stacker (see chapter 23).
3.2.6 System size
The maximum size of a single Praesideo system is
limited by the maximum number of nodes in a system,
which is 63, and the maximum length of the system bus,
which depends on the actual number of nodes in use.
See section 31.4 and 31.5 for details.
The mandatory network controller occupies 3 nodes,
leaving 60 nodes for other system elements, such as
amplifiers and call stations. Different models of
Praesideo power amplifiers have 1 - 4 outputs per
occupied node and each output can serve an
independent voice alarm zone. This adds up to a
maximum of 240 voice alarm zones for a single system.
This number can be increased by coupling of multiple
subsystems, as indicated in section 32.6. Alternatively,
the maximum number of voice alarm zones can be
increased by using a combination of basic amplifiers
and multi channel interfaces, see section 9 and 10. A
multi channel interface occupies only 1 node and can
drive 14 independent voice alarm zones. For response
time reasons it is recommended not to use more than 20
multi channel interfaces in a system. Together with the
other power amplifiers and call stations, this yields a
practical limit of some 400 voice alarm zones in a single
system.
3.3 Types
3.3.1 Introduction
As mentioned before, Praesideo uses the following types
of calls:
• BGM (background music) calls (see section 3.3.2).
• Normal calls (see section 3.3.3).
• Emergency calls (see section 3.3.4).
3.3.2 BGM calls
BGM (background music) calls are typically used to
distribute background music. Their content consists of
an audio signal from a BGM source, such as a CD
player or a tuner. By default, BGM calls are partial calls.
Zones can be added to the routing of a BGM call at any
time. If an added zone is already in use by another call
with the same priority or higher, the BGM call will not
be routed to that zone until it has been released by the
other call.
3.3.3 Normal calls
Normal calls typically contain live speech and
optionally chimes and prerecorded messages. The
content of normal calls is defined by a call macro (see
section 3.2.3). Normal calls can be partial, non-partial,
or stacked.
3.3.4 Emergency calls
Emergency calls are similar to normal calls (see
section 3.2.3). The major difference is that emergency
calls put the system in the emergency state and are
always partial. In the emergency state, Praesideo stops
all BGM calls and normal calls.