User Guide

Installation Instructions
NHB–3
Technical Documentation
PAMS
Original 26/97
6
Power Distribution
The main supply for car kit is obtained from the vehicle battery, the supply volt-
age may vary between 9 and 16 volts. Both the positive voltage and the
grounding are taken directly from the battery, unless the vehicle has other main
voltage than + 12 V. This minimizes the risk of disturbances from or to the tele-
phone as well as guarantees loss–free power distribution.
The connections to the battery should be carried out with care. Both the nega-
tive and positive leads have 4 A fuses, which must always be used. If a fuse
blows, replace it only with the same type and size fuse.
The power cables should be routed so that possible sources of disturbances
are avoided. Also ABS–sencors and like should be avoided as far as possible.
If the vehicle has + 24 V electrical system (trucks, all–terrain vehicles , etc.), an
external voltage reducer must be used. Since the properties of the reducer are
critical, it is recommended to use a reducer supplied by the manufacturer. This
reducer has good protections against transients produced by vehicles electrical
system and it is also capable to maintain stabile output during rapid changes in
load current.
Some vehicles have a main switch (e.g. gas trucks), which separates the ve-
hicles chassis from the negative lead of the battery. Under no circumstances do
not pass this switch, i.e. the grounding of the reducer must be taken from the
body of the vehicle, NOT
directly from the battery.
DO NOT INSTALL REDUCER:
–
TO ENGINE COMPARTMENT
– WHERE THERE ISN’T ADEQUATE AMOUNT OF AIR FOR COOLING (UNDER THE
CARPET, ETC.)
– WHERE THERE IS RISK OF MOISTURE (CONDENSATED WATER, ETC.)