You can change any of the BNC outputs on the back of the AardSync II

BNC #1 256x OR 1x word clock
BNC #2 256x OR 1x word clock
BNC #3 1X OR 2X Word Clock (2X is for 88.2/96kHz)*
BNC #4 1X OR 2X Word Clock (2X is for 88.2/96kHz)*
AES/EBU outputs #5 & #6 are not changeable
BNC Video Input is not changeable

*BNC #3 & #4 are only changeable with S/N 3022491 or higher

To open the AardSync II and access the jumpers, remove the back panel and slide the top of the unit backwards. The front panel must not be removed. On the back panel, first remove the hex nuts on the BNC connectors, then remove the back panel screws and take off the back panel and plastic bezel. Then slide the top of the AardSync II until it comes off.