18 Jun
2011
18 Jun
'11
3:58 p.m.
Hi,
If I have a prolific usb to serial converter can I be sure that the
voltage levels that I get is 3.3V and not 5V.
My serial cable seems to be fine. I have done a loopback test and its
echoing whatever I have typed using hyperterminal.
My mobile phone's audio jack is also fine. I am able to use the hands
free feature and listen to the voice.
I hence feel that the 2.5mm male connector of the serial cable is not
properly connecting to the audio jack of the phone though it sits
properly.
Is there a way I can rectify this without buying a new serial cable?
Regards,
RM
On Mon, Jun 13, 2011 at 12:45 AM, Arne <zachso(a)arcor.de> wrote:
the 3v3 version of max232 is max3232, but this isnt what he needs.
RM, you need a usb->RS232 only if you have no RS232 at one of you
computers/notebooks available. if you have a normal RS232-port you have
already everything you need and can use you cable
bye
arne
On Sun, 12 Jun 2011 20:53:49 +0200
Sébastien Lorquet <squalyl(a)gmail.com> wrote:
If you want to use a basic serial port, use a
3.3V version of the
good ol' MAX232 (maybe MAX202? can't remember)
Sebastien
On Sun, Jun 12, 2011 at 8:20 PM, Alexander Huemer
<alexander.huemer(a)xx.vu>wrote;wrote:
> On Sun, Jun 12, 2011 at 11:11:37PM +0530, R M wrote:
> > Why do I need a USB/RS232 cable ?
> >
> > If its a laptop, I can understand that they don't come with a
> > serial port
> so
> > you need the converter.
> >
> > Many PCs come with a serial port.
> >
> > Can I not connect the serial version of the T191 unlock cable to
> > PC
> serial
> > port?
> You could, but the RS232 ports that are often present on ATX-style
> mainboards provide 12V, which is too much for the phone.
> >
> > As far as I understand, the T191 unlock cable is used to convert
> > RS232 signal level to 3.3V required by C128.
> no. A serial T191 cable does nothing by itself.
> >
> > Since I was able to get hold of a serial version of T191 unlock
> > cable as
> I
> > told you in the begining of the mail, I also purchased a USB to
> > Serial converter. Its a BAFO BF-810.
> > Its based on Prolific chipset.
> Unfortunately the prolific chips seem to not work as well for this
> purpose as the FTDI chips.
> >
> > So I connected first the USB/RS232 converter ju(BAFO BF-810) and
> > then
> the
> > serial version of the T191 unlock cable.
> >
> > Is this the right way ?
> > OR
> > Can I just connect the USB/R232 converter (based on Prolific
> > chipset) and the use a cable which contains DB9 female on one
> > side and 2.5mm jack on
> the
> > other?
> I don't get the difference between those two ways.
> >
> > I am asking the second question because you have mentioned in the
> > wiki
> under
> > Hints and Warnings like this:
> >
> > If you don't use a 3.3V (low voltage TTL, LVCMOS) serial port you
> > can fry your phone! (internally, it connects to the IO-pins of
> > the baseband processor which run at 2.8V). *Don't connect
> > directly to your PCs serial port (running at +/- 12V!).*
> This warning wants to tell you that you should use a USB<-->RS232
> converter and not use an onboard port of a PC.
>
> Kind regards
> -Alex
>
>