Bosch INTELLIVOX DDC LBC 325X - Manual (Page 12)

3. Appendix.
3.1 Reference part list.
Connectors for external wiring.
Table 3 Intellivox external connectors details.
Other installation related accessories.
Table 4 Specific installation related accessories.
Other network related accessories.
Table 5 Specific network related accessories
3.2Grounding strategy.
The ground (GND) terminals on the electronics
module serve different purposes.
1. Safety. The GND terminal located at the mains
IEC connector provides a direct low impedance
path from the metal parts of the chassis to ground.
In conjunction with a proper designed mains
distribution network, this offers extra safety in
situations where the standard class 2 insulation is
not sufficient (fire, moisture etc.). Always connect
the IEC ground terminal.
2. Reduction of RF emission. Although the
Intellivox electronics module is well shielded and
external connections are de-coupled to prevent RF
emission from the internal high speed digital
circuits, this protection will not work properly when
the chassis has no solid ground reference.
3. Immunity. The GND terminal shorts currents
which are induced by (RF) fields in the signal
cables effectively to chassis-ground, provided that
the cable shield is of sufficiently low impedance.
To make things even more complex, the RS-485
terminal of the chassis also has a DGND pin, while the
ambient SPL/temperature terminal has both GND and
AGND pins.
The pins labeled GND are connected directly to the
chassis.
The RS-485 DGND pin is not a ground pin, but serves
as a reference for the RS-485 AB and YZ wires.
Although the DGND pin should be connected to the
shielding of the RS-485 cable (when in use), DGND
(and ABYZ) has no relation to GND except for the
fact that the voltage between DGND and GND is
clamped to a maximum voltage of 50 V for reasons of
safety and immunity. In an installation with a
connected network, the RS-485 cable shield must be
grounded at some central position.
• DGND should not be connected to any other
ground pin (GND or AGND) on the chassis.
Intellivox DDC | Installation Manual | Appendix
Bosch Security Systems | July 2003
EN | 13
Terminal Description Manufacturer Manufacturer code
RS-485 Wago cage clamp connector 5 pin
female 5 mm pitch WAGO 231-105/026-000
Audio input Wago cage clamp connector 6 pin
female 5 mm pitch WAGO 231-106/026-000
Failure, Fan, Ambient
SPL and Temperature Wago cage clamp connector 5 pin
male 5 mm pitch WAGO 231-605
Description Type Number
Intellivox swivel bracket 90° LBC 3270/00
Intellivox swivel bracket 45° LBC 3271/00
Ambient mic. and temperature sensor LBC 3262/00
Description Type Number
Program set
(Adapter cable+RS-232 to RS-485
adapter+ WinControl CD-Rom) LBC 3260/00