Dcn Design; Introduction; Calculation Tool; Concepts - Bosch DCN Next Generation Installation & User's Instructions

DCN Next Generation | Installation and User Instructions | System Design and Planning
1

DCN design

1. 1

Introduction

The DCN Next Generation has two parts: the DCN and
the optical network. This chapter tells how to design the
DCN.
1.2

Calculation tool

The calculation tool makes the planning and design of
the DCN easier. You can find the calculation tool on the
CD-ROM that is supplied with your system.
1.3

Concepts

1.3.1 Introduction
This section gives necessary data to understand the
limitations in section 1.4.
1.3.2 Trunk and tap-off sockets
The DCN uses two types of socket:
• DCN trunk sockets
Use the DCN trunk sockets to make a loop-through
in the trunk of the DCN.
• DCN tap-off sockets
Use the DCN tap-off sockets to make more branches
in the DCN. A DCN tap-off socket always
regenerates the digital DCN signal.
1.3.3 Cables
Many devices used in the DCN have a 2 m cable. If
necessary the extension cable (LBB4116) can extend the
device cables.
1.4

Limits

Make sure these limits are not exceeded when you
design the DCN:
Limit 1: Control capacity
The maximum number of active devices in a DCN that
a central control unit can control is 245. For the
maximum number of active devices that a multi CCU
can control, refer to section 2.7.3. The number of
passive devices is without limit (refer to section 1.5).
Bosch Security Systems | 2007-02 | 9922 141 70525
Limit 2: Power capacity
• The maximum power that one DCN socket of the
central control unit can supply is 65 W.
• The total power that the DCN sockets of the central
control unit can supply is 130 W.
• The maximum power that one DCN socket of the
extension power supply can supply is 85 W
• The total power that the DCN sockets of the
extension power supply can supply is 255 W.
Refer to section 1.6.
Limit 3: Loop-throughs
The maximum number of loop-throughs in succession is
50. If there are more than 50 loop-throughs, the signal
must be regenerated with a trunk splitter (LBB4114/00).
Limit 4: Tap-off connections
The maximum number of tap-off connections in
succession between the central control unit and the last
tap-off in a branch is four. If there are more than four
tap-off connections in succession, the system does not
operate correctly.
Limit 5: Cable lengths
Refer to section 1.7:
• With regenerative tap-offs, the maximum cable
length is 250 m from the central control unit to the
furthest device in any branch of the DCN.
• The maximum cable length from the central control
unit to the first regenerative tap-off is 100 m.
• The maximum length of the cable between
regenerative tap-offs is 100 m.
• Open-ended cables can cause an incorrect operation
of the system.
Note
The total cable length includes the 2 m long
device cables.
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