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Roop

join:2003-11-15
Ottawa, ON
reply to Roop

Re: exploring the alcatel lucent cellpipe 7130

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the contraption in the picture allowed me to dump the serial console boot sequence. here's how i did it. i'm hoping this allows others to make similar (hopefully better less complicated setups). maybe from their we can do more interesting things like enable telnet and dump firmwares or what have you.

so the serial port on the back of my cellpipe works fine, at least for reading. i haven't tried writing yet.

the picture is the cellpipe PCB on the right. connected are the black wire (ground) and red wire to the serial transmit. there's no need to dissamble it btw.

in the middle is an arduino 2009/duemillenova USB which i'm using as my 3.3v TTL to seral to USB converter. The red wire from the cellpipe connects to yellow, then white to the arduino. SPECIAL NOTE: leaving the arduino connected at boot time prevents any output. right after turn on the cell pipe, you plug the white wire in and get output. the black wire from the cell pipe which turns into white is the ground. i plug this into arduino's ground to ensure the same reference.

on the far left is my crappy oscilloscope. i was able to measure a single bit width with it of approximately 10.6 microseconds which allowed me to approximate that to 57600 baud, (8N1 was guessed). here's the basic arduino code i used. note the lack of writing if anyone can fix that.

last note in this: the arduino is 5v TTL, the cellpipe is 3.3v TTL. this makes me a bit hesitant to simply wire the arduino's TX to the cellpipe's RX just yet.

void setup()  
{
  Serial.begin(57600);
}
 
void loop()                     // run over and over again
{
 
  if(Serial.available()) {
    char bytes = Serial.read();
    Serial.print(bytes);
    
    //Serial.println(Serial.read());
  }
 
}