Regarding the cable from Dealextreme

Sébastien Lorquet squalyl at
Thu Mar 18 07:07:23 UTC 2010


You can now be sure: the 3.3v part is the MAX 3232.
Other parts exists that need smaller capacitors (100nF) instead of 1-10µF
required by the "grand father" MAX232 :)


On Thu, Mar 18, 2010 at 8:52 AM, Dieter Spaar <spaar at>wrote:

> Hello Lubomir,
> On Thu, 18 Mar 2010 01:00:44 +0100, "Lubomir Schmidt" <
> gentoo.lubomir at> wrote:
> >
> > How can i change the cable to get it working? What is a
> > level-converter and where can i get such?
> The level of the RS-232 interface is specified to be -3V..-15V for a
> logic one and +3V..+15V for a logic zero, typically -12V and +12V is
> used. The phone uses 0V and 3.2V. So you need a level-converter between
> the RS-232 port of a PC and the phone.
> The simple solution is to use a ready-made data cable with a built-in
> level-converter, they cost around 9.00 EUR on ebay Germany including
> shipping, either as USB or RS-232 variant. If you really want to build
> your own level-converter, you can for example use the MAX232 IC. The
> MAX232 is for TTL level (0V and 5V), I think there is a variant for
> 3.2V available, however I am not 100% sure.
> Best regards,
>  Dieter
> --
> Dieter Spaar, Germany                           spaar at
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