AT OK does not work !!!


#1

Hi,
I notice that on every module Q24, Q26 we have the next problem:

AT answers OK, thanks it works but
AAT does not answer anything while AAAT answers OK.

This is autobaud probelm. I am working with some old machine and I can not change the way it sends at commands.

Is there something that can be done in order for the module to answer OK when it receives AAT ???

Thanks,
Sladj.


#2

can’t you just turn off Autobaud, then :question:


#3

With +IPR=0 or +IPR= any speed the result is the same on AAT the module does not answer anything …


#4

As the module expects everything to start with AT, I think your best bet is to add another layer between the old machine and the GSM module, that can emulate the expected behaviour but forward everything else.

Anyway, trying to type AAT in a terminal I only get echo from AA, the third input character disappears in limbo. Typing AAAAT gives OK here with the third A never getting echoed.
I have no idea what is happening internally to create this behaviour but it certainly is odd.


#5

I’ve just tried it, and it seems that every third character gets discarded:

Type “AT” echoes “AT” and gives OK;
Type “AAT” echoes “AA” and gives no reply;
Type “AAAT” echoes “AAT” and gives no reply;
Type “AAAAT” echoes “AAAT” and gives OK;
Type “AAAAAT” echoes “AAAA” and gives no reply;
Type “AAAAAAT” echoes “AAAAT” and gives no reply;
Type “AAAAAAAT” echoes “AAAAAT” and gives OK…

Neither have I, but it looks like there’s some sort of state machine going on, which gets reset at every 3rd character…


#6

Of course, the basis of the AT command interface is that every command starts with “AT” - so, if you do anything else, you are into the world of Undefined Behaviour, where anything can happen… :open_mouth:


#7

Hi folks,

Just playing with beta OS 6.62 the situation is new:

Thx awneil i copied your AT response structure and updated for this version:

Type “AT” echoes “AT” and gives OK;
Type “AAT” echoes “AAT” and gives no reply;
Type “AAAT” echoes “AAAT” and gives OK;
Type “AAAAT” echoes “AAAAT” and gives no reply
Type “AAAAAT” echoes “AAAAAT” and gives OK
Type “AAAAAAT” echoes “AAAAAAT” and gives no reply;
Type “AAAAAAAT” echoes “AAAAAAAT” and gives OK…

looks like this state machine is working better.

I just wanted to write down my ‘funny’ experience with anno OS 6.60 that i write ati and press down the ‘i’ button and it will give like this ‘atiiiiiiiiiiiiiiiiiiiiiiiiiiiiiii’ At the x. ‘i’ character the module rebooted. I tried it on OS 6.62 beta and this bug is there, the module just reboots. Holy s***! I think it should be written well once, not always changed. The situation is the same with ‘ATTTTTTTTTTTTTTT…’ (much ‘T’ character), and the module reboots.

Cheers,

tom


#8

Hi,

I do not want to be “rabat-joie”, but I think that there should not be “Undefined Behaviour” with machines (modems). That why we are here.

Many old softwares sends AAT in order to give a chance to autobaud to recognize the speed and from HAYES point of view that is correct.

None of the firmwares can recognize AAT and none of the firmwares can recognize AT in 7bits with parity.
I did mention this problem a long time ago. I am sure that Wavecom will soon pleasantly surprise us all.