Cannot change the S2 register

Hi all,

I am using the Q2686RD, firmware 7.43, Open AT OS 6.32.

I am trying to change the escape character from a ‘+’ (ASCII 043) to a ‘!’ (ASCII 033) by using the S2 register. To change the S2 register, one would normally enter ATS2=033, but this returns with the word ERROR. It seems that trying to change it to any character other than 043, displays ERROR.

Does anyone know if this can be changed on the module, or is it permanently fixed? The ‘AT Commands Interface Guide for Firmware 7.43’ throws no light on this subject at all. I have worked with many makes of modem, and all of them allows the S2 register to be changed. Am I doing something wrong?


ISTR trying this once long ago, and coming to the conclusion that the S2 register is ignored.


Thanks awneil.

It’s a pity that there is documentation failure again. :angry:

I think you’ll find that S12 (the guard time) is also ignored…



I think only S0 register is accessible , access to all the other registers is
not supported and that is why only ATS0 is documented.