Bosch ISW-BHB1-WX Service manual

TECHNICAL BULLETIN
Intrusion wLSN Wireless Devices
Signal-to-Noise Ratio Values March 4, 2010
Issue Severity: Products Affected:
High: Act immediately
Medium: Bosch Security Systems, Inc.
strongly recommends you take the action(s)
described below.
Low: Advisory
•wLSN Hub (ISW-BHB1-WX)
•wLSN Installation Tool
(ISW-BIT1-HAX, -HBX, -HCX)
•Compatible wLSN Devices
1.0 Issue
The Signal-to-Noise Ratio (SNR) recommendations that are shown in the wLSN Reference Guide
(P/N: F01U009440) do not adequately ensure a trouble-free wireless installation in certain European markets
where multi-path signal fading might be present. Table 1 shows the SNR values that are currently published in
the reference guide.
Table 1: SNR Values using wLSN Hub (ISW-BHB1-WX)
Signal-to-Noise Ratio Signal Strength
<9 dB Unacceptable
9 dB Marginal (not recommended)
13 dB Acceptable
16 dB Good
20 dB Very good
22 dB Excellent
When the SNR values shown in Table 1 are used to measure signal strength, signal strength can fluctuate
significantly in locations where multi-path signal fading is present. As a result, the device might not be able to
communicate with the hub. If a communication failure occurs and is not resolved within the defined supervision
window, the control panel sends a missing device report to the central monitoring station.

© Bosch Security Systems, Inc. 2010
130 Perinton Parkway, Fairport, NY 14450 USA
www.boschsecurity.com
TBI 07-31-09_wLSN_SRN-02
Technical Bulletin
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wLSN Wireless Device
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2.0 Resolution
For more accurate measurements, use the SNR values as shown in Table 2 when performing an RFSS test.
Use the wLSN Installation Tool only in Mode 3. Do not use the Installation Tool in Modes 1 or 2,
and do not use the individual wLSN devices to determine an acceptable SNR. The SNR
measurements in Modes 1 and 2 and directly from the devices do not correspond to the
recommended values indicated in Table 2.
Table 2: Revised SNR Values using wLSN Hub (ISW-BHB1-WX)
Signal-to-Noise Ratio Signal Strength
<30 dB Unacceptable
30 dB Marginal (not recommended)
35 dB Acceptable
40 dB Good
45 dB Very good
50 dB Excellent
To ensure that wLSN devices are operating at acceptable SNR values:
1. Connect to the control panel using a telephone.
Refer to the control panel documentation for connection options.
2. When prompted, enter the installer passcode.
3. Press [1] to enter the System Maintenance Menu, and then press [6] to enter the Wireless Configuration
Menu.
4. From the Wireless Configuration Menu, press [7]. When the control panel announces “Enter the number of
the programming item,” press [2] for signal strength.
5. When the control panel asks for a point number, press [0][1] to [3][2] for Points 1-32, or [3][5] to [3][8] for
Outputs 5-8.
6. After a point or output number is entered, the hub communicates with the selected device to retrieve the
signal strength. The control panel announces the signal strength as two alphanumeric characters. For
example, “3 5.” Refer to Table 3 to cross reference the spoken value to an SNR value.
Table 3: SNR Values from the Control Panel
Control Panel Value SNR Signal Strength
01 - 09 2 dB – 14 dB
0A – 0F 15 dB – 23 dB
10 – 13 24 dB – 29 dB
Unacceptable
14 – 16 30 dB – 33 dB Marginal
17 – 1A 35 dB – 39 dB Acceptable
1B – 1D 41 dB – 44 dB Good
1E – 20 45 dB – 48 dB Very good
21 – 32 50 dB – 75 dB Excellent