Note that the BSAP 1935 is a dual-radio device; it has both a 2.4 GHz (802.11b/g/n) and 5 GHz (802.11a/n) radio chain. There be labels near each connector on the BSAP to describe the radio associated with the connector. The connectors are on the sides of the AP. Assuming you are using a 3rd party antenna, it should also state which radio its connectors are used with. Just match these up as best as you can, but ideally you would use all the connectors on the AP. You might also note that the BSAP 1920 is a 2x2 device. Perhaps you might consider using that.
Also, maybe you could post some images of your antenna, or provide a few more details of the application.
I know the diference between 1925 and 1935 AP's. And you are right, if we have antenne 2x2 MIMO, we have to use BSAP-1935. But in our case we install pilot zone with outdoor 2x2 MIMO omni antenna and would like to test both 1925 and 1935 AP's using the same antenna. In vwlan (Configure/Wreless/Template) we can use mode One, Two or Three antennas. So the question is - if we use One antenna mode - which one of three connectors is used on BSAP-1935? And if we use Two antenna mode - wich two of three connectors are used on BSAP-1935?
Sorry, I mean - if we have antenna 2x2 MIMO, we have to use BSAP-1925