How's the pin connection between arduino and GSMSim900D? and view the activity using hyperterminal? thanks

 

Connect rx to tx and tx to rx? Check that they run on the same voltage?

 

What protocol/bus does the GSM communicate to the Arduino with? UART? I2C? SPI?

The answer is a Bus Pirate, though I'm not entirely sure what your question is.

 

i connect the rx-tx of arduino to the, tx-rx of RS232 to ttl converter. just want to test At-commands
how i am gonna connect the GSM? tnx

 

up............................

 

I am not sure what you expect, but most people here don´t read other´s minds and don´t have other superhuman abilites. I have no idea what that GSMSim900D is or how it is connected. So unless you post a datsheet and a diagram of how you want to connect it you will get very little good responses. And bumping the thread won´t get you much help either.

 

This thread is bothering me to continue seeing since the OP wants answers with minimal information, as such, I will jump in here...

OP, is this the device datasheet?

So, are you trying to communicate with the GSM module through UART, or SPI? You mentioned UART connections, from the Arduino to the computer, so you'll either have to do a software UART, or use the SPI interface...

Draw a schematic to help the people trying to help you.

 

Sorry for the lack of information.

this is the GSM SIM900D module

and this the arduino clone i am using

since there is only one tx-rx pin in arduino and also in the GSM module,. how can i interface the RS232 to ttl converter?
or anyone of you try doing that without bricking one of the device? tnx

 

And those DTR, DCD, RTS and CTS pins are there just for fun? If the modem needs them to communicate then you will have to connect those as well. But I have a feeling that you need to put your own program inside the modem, so I guess that is up to you.

Also, why do you need RS232-to ttl converter when both arduino and the modem use TTL levels? (one could be 5V and the other 3.3V though)

 

Sorry for the lack of information.

How about answering some questions?