Car Radio Muting Crm; Ignition Sense Igns - Nokia 9000i Service Manual

RAE/RAK–1N
CARK60 Installation Guide

Car Radio Muting CRM

The Communicator offers a feature that can mute the car radio
automatically during a conversation. This feature is convenient and
provides for safer hands–free operation. The Car Radio Muting feature is
based on a 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 this should be connected in series with the car radio
main supply. A 200 mA fuse should be used to protect the XCRM output in
event of a 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 marked ACC or +MEM), but to install
the relay in the main supply feed.
Another possibility is to use a special muting unit, 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 your Communicator from draining the
car battery by executing an auto power off in 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 volt potential that is controlled by the ignition
key. Do not connect it directly to the high voltage sections of the ignition
circuit.
All installations should take into account any special requirements of the
customer. However, should the customer require an installation that is
illegal or unsafe, these facts must be pointed out to the customer and a
policy of non–compliance adopted.
Page 10
87A
GND
CAR
RADIO
87
85
To XCRM line
(yellow wire)
Figure 4. Radio Muting Circuit
Technical Documentation
Bosch P/N 0–332–204–150
12 V, 30 A. SPDT
12 V d.c.
30
Supply for
car radio
12 V d.c.
86
Fuse 200 mA
(not supplied)
After Sales
Original, 08/96