Use of ZS

Hello , I am working with two XBEE USB S2 modems and one od them has the XB24B-ZB firmware . I use the X-CTU and I would be interesting in knowing what is the ZS ( Zigbee Stack Profile used for . It has three possible values (0-1-2) why are they for .
The second question is what is the difference between the OI and the OP ( Operating 16 bit PAN ID and Operating PAN ID ) .

Thanks

The ZS is the zigbee protocol that will be used. My best luck was with option 2 which is Zigbee Pro. As for OP and OI, OP is the 32 bit pan the unit is using and OI is the 16 bit pan. The OI was implemented in cases where two coordinators shared the same channel and 32 bit pan. The 16 bit pan is then randomly selected to make sure that the two networks stay independent.

The OEM manual for the ZB rf modules would be a good source of PAN ID explanations as well as AT command meanings.