Note: your Ph-Pro / Powerhouse / CS02 system must have EPROM version 2007c or newer to access all 28 functions from a cab. check your version here: https://ncedcc.zendesk.com/hc/en-us/articles/201873725-PH-Pro-Powerhouse-CS02-What-Version-do-I-have-
The option key is a programmable key that can be set to do various functions
The default value for the option key is either as a brake (value=94) or a function shift key (value=122)
to change this you need to get into cab setup mode and change the value for the option key.