Re: [tlug] Japanese Call Display

[Jim Tittsler <jwt-tlug@example.com>]

On Apr 3, 2006, at 10:08, David Bennett wrote:

> I am wondering if anyone knows anything about Japan's caller ID
> systems and if in fact their is a difference (ie. will it not work.)

I don't have access to the specs any more, but they are different.   
Both use FSK, but the frequencies are slightly different (Bell 202 vs  
V.23).  The timing is also different.  (The US system sends the ID  
between the first and second ring, and the Japanese system sends  
after a special short first ring and polarity reversal.  I think the  
pause after the ring and the length of the preamble before the first  
data bit are also different, but that probably isn't important since  
nobody decodes in the analog domain any more.)

It is possible to handle both (check the zaptel work from Asterisk),  
but there was probably no advantage for your phone manufacturer to do  
so.



--
Jim Tittsler  7J1AJH/AI8A  Tokyo                     GPG: 0x01159DB6
http://www.qsl.net/7j1ajh/                       QRP/Satellites/APRS
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