Communicating Via serial port with GSM modem - serial-port

I am using a EVB for siemens MC45 GSM modem. Itried to send At commands to it via serial port with Hyperterminal in windows (both Xp and 7). But the hyperterminal window is showing that I am connected but when I type something it doesnot show my writings. and no response from the GSM modem is received.
What Can I do ?

The problem is with your hyper terminal settings when you are connecting with the modem.
Use these settings: Baud rate:9600 data bits:8 stop bits:1 parity bits: none flow control:none Should work now. Also check whether you are communicating with the correct port

Have you configured the hyperterminal session properly? I think you will probably need to set it up as follows:
BaudRate 19200
Databit 8
No Parity
Stopbit 1
No Flow control

Related

How should i test if UART port is working?

I wanted to test if my UART(ttyMT1) is working on my custom board (android project). I have 2 UARTs on my board- ttyMT0 & ttyMT1. UART ttymt0 is my debug port. I have microcom on my board as well.
Test1:
I connected Tx and Rx of ttyMT1 with a female to female jumper wire. Then, on my ADB, i opened microcom for ttyMT1 using the below command:
microcom -s 115200 /dev/ttyMT1
On my debug port (using minicom), ttyMT0, I transmitted to ttyMT1 using echo as shown :
echo -ne 'Hello' > /dev/ttyMT1
and i was able to get the transmitted data print (HELLO) on ttyMT1.
What i wanted to know was, is this enough to verify that my UART ttyMT1 is working fine or do i need to try something else?
Test2:
What i tried again was to connect ttyMT0 to my PC's usb port and ttyMT1 to another USB port of my PC using 2 separate USB to UART connectors. Then i opened 2 minicom, one for each and tried to transmit the same Hello from ttyMT0 to ttyMT1 (ttyMT0 shows as ttyUSB0 on my PC and ttyMT1 as ttyUSB1). But i didn't receive any print on ttyMT1. Why is that?.
p.s. I'm unable to type anything on ttyMT1. I probed ttyMT1 on Oscilloscope and i got the Tx signal but I didn't get anything on my scope when I probed on Rx.
I think you need to have SELinux permission to access serial port in android. However check this code here to read serial port : https://programmer.help/blogs/serial-port-operation-with-jni-method-under-android.html. It will require you JNI.

Unable to sniff serial port. Weird behavior

Trying to reverse an engineer a program that communicates with a device through a COM PORT. From monitoring the program, it sends 4 bytes of 0x00 and then the device replies back with the same and switches to flash mode. When I send the same bytes, the device does not respond, and in fact, no matter what I send, the serial port monitor says 0x00 is being written.
I've tried several different com port monitors, tried several different baud rates, flush com port before sending the command. Nothing seems to work. What could cause this type of issue?
no matter what I send, the serial port monitor says 0x00
From what you describe it seems like the serial sniffer you use is faulty.
Serial port sniffer I'm using successfully is this Serial Analyzer.

SIM900 module not responding on hardware COM port

I've got my sim900 module working with arduino by using their software serial library, however, I want to eliminate arduino from the equation and have serial communication directly to sim900 module.
I'm using putty as my terminal emulator. It's serial is configured to COM1 19200 8 N 1 the same as device manager configuration for this port.
I connect straight from hardware serial on my PCs motherboard into serial-to-ttl interface board which connects to sim900 module. The board has 4 pins - VCC GND TX RX. They're all connected to my sim900 hardware serial as follows: VCC=5V GND=GND TX=TX RX=RX (Yes I know that it's always actually TX=RX and RX=TX, but when I connect it that way my interface board doesn't blink any led to indicate a transfer whereas it does when I connect TX=TX and RX=RX). The switch on the module is set to hardware serial pins as well.
So the only thing that happens when I send AT commands such as AT or ATI and press enter is that puttys cursor comes back to the beginning of command that I typed. No response.
I'm thinking that I'm not doing something that the arduinos software serial port is doing when it sends commands to sim900.
Can anyone help please ? It's literally been days of trying different configurations with no results.
In that time besides getting sim900 working with arduino software serial I verified that the hardware serial port on my motherboard is working correctly and the interface board is working correctly as well.

Implementing I2C slave with FT201XB via USB

I've been trying to test a FT201XQ USB-I2C breakout board: UMFT201XB-01, so I can connect it to a master device such as an Arduino and sniff what that device is sending through I2C.
To see the output of the slave device I have successfully configured a Virtual COM PORT by installing the D2XX drivers provided by ftdchip.com. I can open the serial port through puTTY and everything seems fine in that regard.
Then, i've loaded the "master_writer" example on my Arduino, which sends 1 byte at a time to an address (0x22 is specified in the UM201XB-01 datasheet as the default address).
Nothing seems to happen in the COM port that i've earlier opened. Do I need to configure/program the FTDI device in some way? In that case, how can I do it, in a general way?
UMFT201XB-01 board http://www.ftdichip.com/Support/Documents/DataSheets/Modules/DS_UMFT201_220_230XB.pdf
Thank you in advance, and sorry if this is a "noob" question : P

Modem responds with junk value for AT Command using serial programming

Background
I am trying to connect to a serial GSM - modem of Wavecom type.
I was able to communicate with the modem using the guide
http://www.easysw.com/~mike/serial/serial.html
on my Ubuntu machine.
but when I tried to connect it through a device with serial port and running on Linux kernel Linux 2.6.14.7-tiny1-WR1.3al_small I get junk data returned. I have tried all of the baud values to connect to the modem. It connected on 115200 baud value when it was working, but the same value does not work from this Kernel. Its a ARM target machine. note : I cross compiled the code for ARM
Question
Do I need a driver for a modem to just be connected through a serial terminal Program ?
Please make sure that the RS232/TTL converter of your ARM board is working correctly. for example you can connect it to your Ubuntu machine at first and transmit something with a terminal program.
question : 1 ) Do i need a driver for Modem to just be connected through a Serial Terminal Program ?
No.You can connect to your GSM modem simply by having a serial port and a terminal program.

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