Hello Lubomir,
On Thu, 18 Mar 2010 01:00:44 +0100, "Lubomir Schmidt" gentoo.lubomir@googlemail.com 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
Hi,
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 :)
Sebastien
On Thu, Mar 18, 2010 at 8:52 AM, Dieter Spaar spaar@mirider.augusta.dewrote:
Hello Lubomir,
On Thu, 18 Mar 2010 01:00:44 +0100, "Lubomir Schmidt" < gentoo.lubomir@googlemail.com> 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@mirider.augusta.de
Hi Dieter,
Zitat von Dieter Spaar spaar@mirider.augusta.de:
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.
Maxim alone has about a dozen variations of the MAX232 (max3232 for 3v3, e.g).
It's much easier to directly go from USB to TTL/3v3 serial ports, the basic breakout boards from Sparkfun (e.g. http://www.watterott.com/de/FTDI-Basic-Breakout-33V) seem to be fine and sell for ?12. Haven't used them on a C123-phone, though.
Chris
baseband-devel@lists.osmocom.org
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Christian Vogel -
Dieter Spaar -
Sébastien Lorquet