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

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

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]> ¦b¶l¥ó news:3f22b0ad$1@shknews01 ¤¤¼¶¼g...
> 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
>
>

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]> ¦b¶l¥ó news:3f22b0ad$1@shknews01 ¤¤¼¶¼g...
> > 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]

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.

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.

[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

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.