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Thread: How to connect mp3/PC to Kenwood HU

  1. #1
    Join Date
    Mar 2004

    How to connect mp3/PC to Kenwood HU

    I have Kenwood kpc-7060R head unit in my car and have a dream to connect my laptop to it.

    I was very happy when I found info about pinout and protocol on this site

    I Ďm using 16F876 as converter to rs232 , spi port to HU and uart to PC.
    So far so good ....., but my HU is an old type with a different protocol and with no CDC to monitor the serial bus, Iím stuck.

    Does anyone have info about the older protocol, log of the serial transfer between CDC and HU, or any thing that can help with this project?


  2. #2
    Join Date
    Mar 2004

    Some info: Kenwood HU to PC

    OK This weekend I have done some test and will share what I get with you:

    Following is for Kenwood head unit with 13pin round plug older than 1999.

    I don't have CD changer so I can't confirm this info, use it at your own risk.

    Pin out is:

    4 3 2 1
    8 7 6 5
    12 11 10 9

    1 REQH OUT Request output to changer; "Low" : Request
    2 GND - Ground
    3 BU + 12 OUT Vcc +12V
    4 CH CON OUT Changer control; "High" : Operation mode "Low" : Standby
    5 CH MUTE IN Mute request from changer; "High" : Mute
    6 A GND - Audio Ground
    7 CH RST OUT Reset output to changer
    8 R AUDIO IN Audio right channel
    9 REQC IN Request input from changer; "Low" : Request
    10 DATAC IN Data input from changer
    11 DATAH OUT Data output to changer
    12 L AUDIO IN Audio left channel
    13 CH CLK I/O Clock input/output for changer

    1. Start with:
    CH MUTE, DATAC: low (0 V) and
    REQC, CH CLK: high (+ 5 V)
    then HU will look for a Changer.
    Pressing [SRC] button give:
    TUNER --> (CD -->) DISK (followed with NO CHANGER) --> TUNER etc.

    2. Get data from HU:
    When changing from TUNER to DISK: CH CON goes from low to high and REQH from high to low. Sending 8 clock pulse to HU give 1 byte followed with REQC low pulse, something like this:

    RQEH -----+ +---------

    CLKC ------+ +-+ +-+ +-+ +-+ +-+ +-+ +-+ +--------------
    +-+ +-+ +-+ +-+ +-+ +-+ +-+ +-+

    REQC ---------------------------------------------+ +------
    when REQC goes low, REQH go high.
    after REQC high, REQH goes low requesting to send another byte to changer, total 6 byte, BA D0 BC F3 D1 D4 .
    after that HU will display NO CHANGER and no audio input if it donít get answer form CDC.

    3. Send data to HU

    Sending data to HU is similar to get data, but I have no info about that. Can you help?

    I have manage to fool the HU to think it has CD-changer connected, but the method is unstable and will not be published now.

    4. Control PC from HU

    When pressing Disk Control Button, HU request to send following 1 byte commands to changer:

    Button down up
    >>| F6 FE
    |<< F7 FE
    Disk + F0 FE
    Disk - F1 FE
    >|| F5 --
    EJECT ?
    SCAN (2) FA
    RDM (3) DE
    REP (4) DC
    D-SCN (5) FB
    M-RDM (6) F2

    As commands are only 1 byte, it is simple task to control MP3 Player, WinAmp etc.

    I hope this info will help someone and maybe someone can share more info.


  3. #3
    Constant Bitrate
    Join Date
    Sep 2003
    Northeast Ohio
    Have you thought about using one of these Kenwood HU adapters ?
    Epia M1000 w/512MB PC2100, Xenarc 700TS, ATI 7500 PCI, OPUS 150 PSU, 2.5 40GB 5400 HDD, 802.11g PCI, Slim Slot DVDR,
    Gyration RF Kybrd, OBDII adpt. + sftwr, XP pro, iGuidance/Royaltek GPS NAV, XMPCR, Kenwd KAC-8401 4 chnl amp, 10" pwd sub

  4. #4
    Join Date
    Mar 2004

    Kenwood CA-C1AUX adapter but

    Yes, I have thought about buying Kenwood CA-C1AUX adapter but

    1. My HU is older than 1999
    2. With this adapter it is not possible to control mp3 player from HU or display text on HU
    3. Electronics is my hobby, so using simple adapter is to easy.


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