Ben Todd explains: addition of SUBS_O bus which is a route-through of SUBS[7:0]
Allows the connected user to determine the station address, without interfering with the SUBS read by the nanoFIP.

Suggested SUBS_O pins:
SUBS_O [7] pin: 148
SUBS_O [6] pin: 147
SUBS_O [5] pin: 146
SUBS_O [4] pin: 145
SUBS_O [3] pin: 144
SUBS_O [2] pin: 143
SUBS_O [1] pin: 139
SUBS_O [0] pin: 138