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  1. #1
    cmyk
    Guest
    Any professional can modify the Japanese CDMA mobile phone to use in US or
    China
    China.

    Need to change language, frequency and unlock code.

    thanks





    See More: Any professional can modify the Japanese CDMA mobile phone to use in US or China




  2. #2
    George
    Guest

    Re: Any professional can modify the Japanese CDMA mobile phone to use in US or China

    As far as I know, Japan mainly use WCDMA, not CDMA2000 used by Sprint or
    Verizon.

    So, theoretically, that might require modifying the RF module and replacing
    the chipset.


    "cmyk" <[email protected]> 在郵件 news:[email protected] 中撰寫...
    > Any professional can modify the Japanese CDMA mobile phone to use in US or
    > China
    > China.
    >
    > Need to change language, frequency and unlock code.
    >
    > thanks
    >
    >






  3. #3
    Tom Randall
    Guest

    Re: Any professional can modify the Japanese CDMA mobile phone to use in US or China

    Not so. KDDI is CDMA2000.

    "George" <[email protected]> wrote in article
    <[email protected]>:
    > As far as I know, Japan mainly use WCDMA, not CDMA2000 used by Sprint or
    > Verizon.
    >
    > So, theoretically, that might require modifying the RF module and replacing
    > the chipset.
    >
    >
    > "cmyk" <[email protected]> 在郵件 news:[email protected] 中撰寫...
    > > Any professional can modify the Japanese CDMA mobile phone to use in US or
    > > China
    > > China.
    > >
    > > Need to change language, frequency and unlock code.
    > >
    > > thanks
    > >
    > >

    >
    >


    [posted via phonescoop.com - free web access to the alt.cellular groups]



  4. #4

    Re: Any professional can modify the Japanese CDMA mobile phone to use in US or China

    On Sun, 27 Jul 2003 00:49:03 +0800, "cmyk" <[email protected]>
    wrote:

    >Any professional can modify the Japanese CDMA mobile phone to use in US or
    >China
    >China.
    >
    >Need to change language, frequency and unlock code.
    >
    >thanks


    For phones from Japan, you'd need the switch the transmit and receive
    frequencies. See the JTAC section of the 3GPP2 standards.

    You'd likely want to change the antennae, too, because the US uses
    1900 MHz for cdma, also, not just 800 MHz.





  5. #5

    Re: Any professional can modify the Japanese CDMA mobile phone to use in US or China

    On Sun, 27 Jul 2003 20:25:19 -0400, "George" <[email protected]>
    wrote:

    >As far as I know, Japan mainly use WCDMA, not CDMA2000 used by Sprint or
    >Verizon.
    >
    >So, theoretically, that might require modifying the RF module and replacing
    >the chipset.


    cdma rollout (IS-95) was March 1999 for IDO as I recall, now called
    au. au rolled out cdma2000 1x April 1, 2002.

    According to Mobile Media Japan the current number of cdma2000 1x
    subscribers in Japan is 8,572,000. The number of FOMA (NTT DoCoMo and
    J-Phone (now Vodaphone) W-CDMA is 589,000, with FOMA @ 534,000 and
    Vodaphone @ 55,000.



  6. #6
    Andrew Shepherd
    Guest

    Re: Any professional can modify the Japanese CDMA mobile phone to use in US or China

    [email protected] wrote in message news:<[email protected]>...
    > On Sun, 27 Jul 2003 00:49:03 +0800, "cmyk" <[email protected]>
    > wrote:
    >
    > >Any professional can modify the Japanese CDMA mobile phone to use in US or
    > >China
    > >China.
    > >
    > >Need to change language, frequency and unlock code.
    > >
    > >thanks

    >
    > For phones from Japan, you'd need the switch the transmit and receive
    > frequencies. See the JTAC section of the 3GPP2 standards.


    The cdma2000 standard has specified nine separate band classes (0
    through 9). Band Class 0 is the traditional Cellular band. Band
    Class 1 is the North American PCS band. Band Class 2 is the TACS
    band. And, finally, Band Class 3 is the J-TACS band, which is the
    band in which TACS, the Motorola analog air-interface very similar to
    AMPS, was deployed in Japan. KDDI has subsequently replaced TACS w/
    its IS-95 followed by IS-2000 deployments, the latter called au, in
    the J-TACS band in Japan.

    If my sources are accurate, the J-TACS bandplan is defined by the
    following:

    887-889 MHz (reverse-link)
    898-901 MHz (reverse-link)
    915-925 MHz (reverse-link)

    832-834 MHz (forward-link)
    843-846 MHz (forward-link)
    860-870 MHz (forward-link)

    The J-TACS paired spectrum offset is 55 MHz, compared to 45 MHz for
    the Cellular band or 80 MHz for the North American PCS band, and the
    forward-link spectrum is unconventionally located lower in frequency
    than the reverse-link spectrum. Thus, converting a Japanese cdma2000
    mobile for use in North America would be an excruciating task for even
    an electrical engineer, not to mention illegal, as the mobile would
    not be an approved device by the FCC, either before or after the
    modification.

    If anyone is interested in a complete list of the nine specified
    cdma2000 band classes, I will be happy to post the remaining upon
    request.

    Andrew
    --
    Andrew Shepherd
    [email protected]
    [email protected]
    http://people.ku.edu/~cinema/wireless/main.html



  7. #7

    Re: Any professional can modify the Japanese CDMA mobile phone to use in US or China

    On 28 Jul 2003 19:51:47 -0700, [email protected] (Andrew Shepherd) wrote:


    >The J-TACS paired spectrum offset is 55 MHz, compared to 45 MHz for
    >the Cellular band or 80 MHz for the North American PCS band, and the
    >forward-link spectrum is unconventionally located lower in frequency
    >than the reverse-link spectrum. Thus, converting a Japanese cdma2000
    >mobile for use in North America would be an excruciating task for even
    >an electrical engineer, not to mention illegal, as the mobile would
    >not be an approved device by the FCC, either before or after the
    >modification.


    If the phone were designed right (and I think Qualcomm's direct
    conversion chips could do this, since they're "zero IF") just change
    the frequencies via the numerically controlled oscillators. This
    leaves the engineering difficulty of a really tunable and efficient RF
    "power amplifier" over a large tuning range.




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