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External Modem and Microcontroller

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glenjoy

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external modem+communication +microcontroller

Is it possible to interface this two? If yes do you have the Pin connections of the external modems and possible how to communicate? Does it has a /CS ENABLE, or simple plug the TX/RX then run an AT command?
 

C-Man

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connect microcontroller to modem

No problem to interface a modem to a microcontroller, simply connect RX, TX and GND (you need for example a MAX232 for the microcontroller) and use AT commands.

You should get the pinout of the modem connector with your modem it is like the PC pinout except RX and TX and the handshake lines are crossed.

Just use a 1:1 cable to connect the modem to the PC (or microcontroller).

best regards
 

glenjoy

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external modem+interfase+micro

I think TX of modem will be the RX of the micro, so therefore RX of modem is TX of micro, else there will be a clash of data, so there is no need to create a driver or somewhat a control signal, just send AT command and that is it?

Have you tried this?

Thanks.

Glenjoy
 

glenjoy

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using microcontrollers connect modem

Btw can give me an example of sending AT command via serial?

Is it as simple as sending the ASCII equivalent of the commands at the serial port?
 

C-Man

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connecting ethernet card to microcontroller

I am using a modem with an 8051.

Simply connect TX of the modem to RX of your micro and RX of the modem to TX of your micro (via MAX232).

Here is an example of sending an AT command to the modem:

code const char COMMANDMODUS[]={'+', '+', '+', 0};

void serial_out(byte zeichen)
{
while(!Transmit)
continue; // warten bis das nächste Zeichen gesendet werden darf

Transmit=FALSE; // dieses Flag wird vom Interrupt gesetzt sobald wieder ein Zeichen an den UART übergeben werden darf
SBUF=zeichen; // und Zeichen an den UART übergeben
}



void string_serial(const char *string)
{
while(*string)
{
serial_out((byte) *string); // Zeichen an den UART übergeben
string++; // und mit dem nächsten Zeichen weitermachen
}
}



void main(void)
{
string_serial(COMMANDMODUS); // das Modem mittels "+++" in den Online-Befehlsmodus umschalten falls beim Reset abgehoben war
}

hope this helps
 

glenjoy

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external modem autoanswer at command

Hi,

I will be coding in Assembly, so will be sending a train of ASCII characters representing the AT Commands, next I will be researching is how to enable the modem as an autoanswer after dialing into it.

Do you have any documents related into this?

Thanks.
 

glenjoy

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microcontroller modem connection

So on auto answer mode, I will just detect a ringing signal then send the signal ATA?

Thanks a lot for the help.
 

eemapir

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modem and gprs connected to microcontroller

I reallywant to know if it is possible to
make modems with micro
having new er in formayion please inform me :eek:
 

C-Man

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how to connent microcontroller to modem

glenjoy said:
So on auto answer mode, I will just detect a ringing signal then send the signal ATA?

Thanks a lot for the help.

Yes simply wait for "RING" from the modem then send "ATA" and wait for "CONNECT ...." afterwards you can communicate.

best regards
 

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