Bosch Appliances Home Security System DS938Z Manuel D’Utilisation

8  © 2012 Bosch Security Systems, Inc.

The use of a Sonalert type device (sounder) will provide an audible 

tone during the time the unit is in alarm. Of the three available connec-

tor pins, the center pin is positive (+) with respect to either outside pin 

(outside pins are common (-)).

Use of the sounder is intended only as an aid for walk testing during 

installation.

3.  Place the cover on the unit, and twist-lock it clockwise into place.

4.  Apply power to the unit.
5.  Wait at least two minutes, after applying power, to start walk tests.

6.  The edge of the coverage pattern is determined when the Alarm/Test 

LED indicator (and optional Sonalert®, if installed) fi rst turns on.

7.  Walk test the unit from all directions to determine the boundaries.
8.  After completion of the walk tests, remove the Sonalert® (if installed).

Be sure the TC6000 and Sonalert leads are dressed through the cut-

out.

Walk testing should be done across the coverage pattern as shown.

1.  Connect a 20,000 ohm/volt (or greater) DC VOM to the Noise Voltage 

connector using the TC6000 as shown.  Set meter scale for about 3.0 

VDC.

2.  The base reference level for reading background noise or target volt-

ages is approximately 2.0 VDC. Installations in quiet environments, 

therefore, will result in a steady meter reading between 1.9 and 2.1 

VDC. Look for areas and sources of thermal disturbances if the meter 

fl uctuates greatly.

Meter readings are very important in determining background distur-

bance levels and catch margin sensitivity.

 F.01U.263.663 | 01 | 05.2012 | 5

Only apply power after all connections have been made and inspected.  

Do not coil excess wiring inside detector. Use no smaller than #22 

AWG (0.8 mm) wire in the terminal strip.

Be sure all wiring is unpowered (de-energized) before routing.

Mounting Base

REAR WIRE

ENTRANCE

WIRE

TIE-DOWNS

(2)

TERMINAL

STRIP

INTERFACE

PINS

MOUNTING

SLOTS (4)

18

Top View of Enclosure

with Cover and Optical Module Removed

ALARM/TEST LED

INDICATOR (3)

SOUNDER

NOISE

VOLTAGE

CONFIGURATION
SWITCHES

COVER

TAMPER

ON

OFF

TEST LEAD 

CUTOUT

ANTI-TAMPER SCREW HOLE 

REQUIRED FOR EN50131 
INSTALLA TIONS

ANTI-T AMPER SCREW HOLE 
REQUIRED FOR EN50131 
INST ALLA TIONS

LO

HI

GAIN SELECT

JUMPER

HI

LO

The DS938Z base will not completely cover a 4-inch square box. Where 

aesthetics are important, a 4-inch octagonal box is recommended.

Mounting to removable ceiling tiles is not recommended unless a 

sandwich is made of the base, ceiling tile, and a back plate behind the 

tile. Covers used for 4-inch octagonal and square boxes make a suitable 

back plate (when used with bolts and wing nuts, as an example).

Figure 2.3: Overview

4.  Firmly mount the base. Depending on local regulations, the base may 

be directly surface mounted using anchors, mollies, or wing-nuts, or 

may be mounted to standard 4-inch octagonal or square electrical 

boxes.