Cavalryman
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Greetings.
I bought GSM module from the ebay recently.
The problem is that i failed to communicate with the module via the PC's rs-232 interface.
I spent quite a time to discover, that GSM module's rs-232 level converter (MAX 232EPE) works OK. What was also discovered, is that GSM module doesn't keep logic "1" on TX pin. It is zero volts there always. TX pin of the UART device should be "1" in idle, right ?
Did somebody have similar problems ? I personally think, that TC35 itself is inoperative because it looks quite old.
GSM module looks like this:
I bought GSM module from the ebay recently.
The problem is that i failed to communicate with the module via the PC's rs-232 interface.
I spent quite a time to discover, that GSM module's rs-232 level converter (MAX 232EPE) works OK. What was also discovered, is that GSM module doesn't keep logic "1" on TX pin. It is zero volts there always. TX pin of the UART device should be "1" in idle, right ?
Did somebody have similar problems ? I personally think, that TC35 itself is inoperative because it looks quite old.
GSM module looks like this: