umery2k75 said:even the gsm module are connected internally with just TX and RX and GND.
Who said that to you? If you are correct, then why do Modem manufacturers include those pins?
Tell me, can you do some modification, if yes, then do as I said.It would work else I don't know any other way, I have explained you the logic for doing this.You just connect those pins of modem on the DB-9 and that's it.Do the shorting,swaping in the wire.You won't change your circuit, your circuit would be the same except it would have other pins connecting on the DB-9 connector as TX,RX and GND.
Still you'll use only TX,RX for communication.Other pins will be loop back to the Modem, just to fool it,thinking it's talking to another modem.
i mean if my gsm module have 5v power supply then my pic module should have 5v also?
umery2k75 said:Thirdly, I haven't read your assembly program, but I must tell you that, there's one more thing which you have to understand and that's the Serial Cable.I have had the similar kind of problem.
The cable by which you interface your GSM module with HyperTerminal is different
The cable by which you interface your GSM module with PIC will be different
The cable that you use with GSM module and with Hyper Terminal has no cross over connection, but when GSM module and PIC will be communicating, RTS and CTS pins should be short at the GSM module side, additionally TX and RX must be swap.I have given you the hint, that's the only way your PIC would communicate with GSM module.I myself have wasted so much time in it, until I discovered this remedy.
If still you're unclear, let me know.I'll tell you how to do it.
Hi everyone,
I also had this problem with module Fargo Maestro 100 GPRS/GSM. But now i can send and receive data between pic16F877 and this module.
First, you must sure that you can tranfer data between PIC and PC
second, you must sure that you can tranfer data between PC and your module GSM.
If it's ok. swap Tx and Rx pin at max232. and try to send data from PIC to module, sometimes it's ok. But it's still not working, you must use DTR pin (pin4 in DB9 of module). Making a change in voltage level at this pin will warn the module that your device is ready(or turn on). Firstly, connect it to the GND then connect it to 12V. The module will response for your command.
ok sir, by the way.. what is the AT command for setting baud rate at saving setting?
thnx
are my connections are correct?
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