Nokia 3310 SMS Application, done:connecting to serial port(linux/win), done:reading some hex like \x00 . . ., problem:write/send command! noresponse

[Terry Reedy]

"Polerio Babao Jr.II" <ptbjrii at hotmail.com> wrote in message
news:52facf1d.0209190533.3048e62c at posting.google.com...
> Greetings: Python Masters
>
> I wanted to create an SMS application using Nokia 3310 with
> DAU-9P(data cable),
<snip>
> When I connect to the port for the first time I get the ser.read()
> output like this \x00\x0c I think. But that's two response is what I
> get on my first connect. After that when I envoke ser.read() again,
I
> get nothing.
<snip>

I know nothing about Nokia but have had experience (and battle scars)
programming serial i/o.  Two suggestions.

First: make *sure* you have serial protocol set right --  baud rate,
data bits, stop bits, parity, handshaking?  Also make sure you have
proper pins active and properly connected.  It is easy to be off.

Second: if you do not have one, get a breakout box that lets you see
activity at the port.  Its the equivalent of having a
volt-ohm-ammeter.  You plug cable into box and run another cable from
box to port.  A simple one just has lights that flash when a signal
passes thru.  More complicated one allows some signal patching.  I got
mine long ago from Inmac.  Would check google for source now.

That you *seem* to be getting response from Nokia and then not is
puzzling.  Breakout box would give you better idea of what is
happening when.

Terry J. Reedy