Audio - Noise From Speakers When Using Cell Phone

VOLUME
3

GROUP
Accessories

NUMBER
1004

MODEL
All

DATE
October 2004

SUBJECT:
AUDIO INTERFERENCE WHEN USING CELLULAR PHONE

This bulletin provides information relating to an intermittent, faint clicking sound from the audio speakers in some vehicles. The noise may be described as either a clicking, popping or static sound from the dash area. This sound may be caused by radio frequency (RF) signals emitted by the occupants wireless cellular phone.





Wireless telephones are hand-held phones with built-in antennas, often called cellular or cell, mobile or PCS phones. Wireless telephones are two-way radios. When a person speaks into a wireless telephone, it picks up the persons voice and converts the sound to radio frequency energy (or radio waves). The radio waves travel through the air until they reach a receiver at a nearby base station or cell tower. The base station then sends the call through the telephone network until it reaches the person you are calling.

When a person receives a call on his/her wireless telephone, the message travels through the telephone network until it reaches a base station close to his/her wireless phone. Then the base station sends out radio waves that are detected by a receiver in his/her telephone, where the signals are changed back into the sound of a voice.

Radio frequency energy from wireless phones can be picked up by electronic devices in the car such as:

^ Audio Receiver

^ Audio Speakers

External Amplifiers (if equipped)

Some wireless telephone providers require the phone to check into nearby base stations periodically for voice mail messages and reception signals. In addition, it informs the cell site if the phone is in range.

The occupant may hear a clicking noise from the speakers when the following occurs:

^ The occupant is making a call

^ The occupant receives a call

^ The wireless phone is checking into a nearby base station

^ The wireless phone changes cell sites

Kia radios are designed to comply with Federal Communication Commission (FCC) rules, which state operation is subject to the following condition:

^ This device (audio receiver) may not cause harmful interference

^ This device must accept any interference received, including interference that may cause undesired operation

To minimize the interference of the radio receiver:

^ Reorient or relocate the wireless phone (increase the separation between the wireless phone and the audio receiver/speakers/external amplifiers)

^ This condition varies, depending on the wireless phone make and model, service provider and geographical area

^ Drive with the wireless phone off to see if the clicking occurs