User's Manual Part 1

Bosch Security Systems | 2007-02 | 9922 141 70691 en
DCN Wireless | Installation and User Instructions | System Design and Planning en | 12
1 Wireless network design
1.1 Introduction
The DCN Wireless has three parts: the wireless
network, the DCN and the optical network. This
chapter tells how to design the wireless network.
1.2 Limits
Limit 1: Control capacity
The maximum number of devices in the wireless
network that the central control unit can control is 150.
Limit 2: Coverage area
For a good operation of the wireless part, all wireless
discussion units need to be in range of the wireless
access point. The wireless access point has a typical
maximum coverage area of 30 m by 30 m. To
determine the exact coverage area the coverage test kit
can be used.
Limit 3: Frequency
The wireless network must operate in a different
frequency band than adjacent wireless computer
networks (refer to section 1.3).
1.3 Frequency band
1.3.1 802.11g specification
The wireless network is based on the 802.11g
specification for WiFi technology. Devices that comply
to the 802.11g specification operate in frequency bands
between 2.4000 and 2.4835 GHz.
1.3.2 Wireless computer networks
Wireless computer networks are also based on the
802.11g specification for WiFi technology. In the
wireless computer networks, 13 overlapping channels
are available (refer to figure 1.1).
1.3.3 Carriers
In the wireless network of DCN Wireless, three
non-overlapping wireless carriers are available (refer to
figure 1.2).
1.3.4 Interference
The wireless network of DCN Wireless can cause
interference on wireless computer networks. You must
make sure the DCN wireless carrier does not overlap
the WLAN channel.
1.3.5 Example
Refer to figure 1.3. In the example, the WLAN channel
is 3. WLAN channel 3 overlaps DCN wireless carriers 0
and 1. Therefore, use DCN wireless carrier 2.
Note
You can change the power value of the wireless
access point (refer to section 11.6.4).
Note
Although the system operates on frequencies
which are license free world wide, you must be
aware of country specific limitations and follow
them.