User Guide

CAR
RADIO
Bosch P/N
0–332–204–150
12 V, 30 A. SPDT
12 V d.c.
12 V d.c.
Supply for
car radio
Fuse 200 mA
(not
supplied)
To XCRM line
(PCH–4/yello
w)
85
87
87A
30
86
PAMS
Technical Documentation
NHD–4
CAR Installation Guide
Page 5
Original 11/97
Car Radio Mute (XCRM)
The phone offers a feature that can mute the car radio automatically
during a conversation. This feature is convenient and provides for safer
handsfree operation. The car radio muting feature based on grounded
line, so it means that in standby, the yellow wire (XCRM) is not grounded
and car radio works normally, but during a call, line is grounded and car
radio is muted. The maximum load that this line can handle is 250 mA.
Note that an auxiliary relay or muting unit must be used when the car
radio doesn’t have a mute feature available.
When a relay is used, it is connected in
series with the car radio main supply.
A 200 mA fuse should be used to
protect the XCRM output
in event ofa short circuit.
Some radios have separate
supplies for amplifiers and
motors, and another for memory
backup purposes. Very often these
radios also have a secret code
system, which activates itself
if a break in the memory supply
is detected. Be careful when installing
the relay not to break the memory supply (usually markedACC or +MEM),
but to install the relay in the main supply feed.
Another possibility is to use a special muting unit (SR59), which mutes the
radio by connecting load resistors to the speaker lines of the car radio.
Four loudspeakers can be muted and the maximum permitted power is 20
watts per channel. The muting unit can also be used as a relay to cut the
main supply feed of the car radio.
Ignition Sense (IGNS)
The ignition sense feature prevents the transceiver from draining the car
battery by executing an auto power off 20 seconds after the ignition key
has been turned off. The blue wire of the power cable is used for the
ignition sense feature. The use of IGNITION SENSE is recommended to
prevent accidental draining of the car’s battery. The wire is connected via
a 200 mA fuse to a 12/24 volts potential that is controlled by the ignition
key. Do not connect it directly to the high voltage sections of the ignition
circuit.
Handset (HSU–1)
An optional handset offers more privacy during the call. The holder is
attached with mounting plate MKE–1 or swivel HHS–1.