Rs 232 Modem detection


for detecting Rs232 in Wireless CPU, do we operate in Normal mode ( BOOT=1) or in Download mode ( BOOT=0)?



I don’t understand what you would like to know… What are you trying to do? Detecting from OpenAT application if something is connected?

Best Regards,


Does Q24 CLASSIC supports Null Modem connection for serial communication


The module does not care what kind of cable you connect to it. You can make a null modem cable to connect two Q24 CLASSIC together if you want to…

The only things you have to consider is to connect TX (out) to some device’s RX pin and RX (in) to some device’s TX pin. The same for Flow Control of course… AND: The signal level have to match!

As awneil mentioned already: See:

Best Regards,


Remember: on a modem (DCE), TX is an input - it is the data to be transmitted by the modem.
Similarly, on a modem, RX is an output - it is the data that has been received by the modem.

Thus, when you connect a DTE to a modem, you connect TX to TX and RX to RX;
But, when you directly connect two DTEs, you need a Null-Modem cable to “crossover” the TX from one DTE to the RX of the other, and vice-versa

Similarly, if you were to connect two modems, you would need a Null-Modem cable

A full null-modem cable will also provide appropriate “cross-overs” for the other control lines…