BTW, I changed the default in the firmware. Now, default for me is SRB1 off, SRB2 off and NO BIAS. But SRB1 actually is very powerful. SRB2 seems very interesting for selecting any electrode as BIAS.

http://openbci.com/forum/index.php?p=/search&Search=bias_out

Looking at the schematic of the 32bit board, I see that the BIAS_OUT and the BIAS_IN signals are shorted together driving an RC circuit, whose output signal is named BIAS_DRV.

Also, on all of our boards, we have connected the BIAS_IN pin to the BIAS_OUT pin, so you can measure it if you like.

i am totally confused on how to connect the pins of ADS1299 namely BIAS_IN, BIAS_INV, BIAS_OUT and BIAS_REF. what does the BIAS_ELEC do? I am desperately in need of help..

You are right tha the BIAS_INV is used as an input from daisy-chained BIAS_OUT pins, to include as many BIAS signals as you like from stacked devices.

That is there is an RC feedback circuit connecting BIAS_INV and BIAS_OUT, BIAS_OUT is connected to BIAS_IN, and finally BIAS_OUT is broken out to supply the bias signal via a dedicated electrode to th