The CS 1000 documentation defines Flexible Features Codes (FFCs) as follows:
Flexible Feature Codes (FFCs) are user-defined numbers of up to four digits that can be used in place of existing Special Prefix (SPRE) codes. With DN Expansion (DNXP) package 150, Flexible Feature Codes (FFCs) can be up to seven digits long. The Flexible Feature Code (FFC) feature allows customers to define different dialing codes for different features. There is no limit to the number of FFCs per prompt as long as each one is unique.
This feature allows the use of digits 0 through 9, and the asterisk (*) and octothorpe (#) to activate features. Special Prefix (SPRE) dialing feature is still supported, with or without the FFC feature enabled. However, the Special Prefix (SPRE) must be assigned in LD 15 in order for FFCs to operate for those features that also use SPRE codes.
The Avaya Aura® Communication Manager Feature Description and Implementation guide defines Feature Access Codes as follows:
A Feature Access Code (FAC) must contain from one to four characters. These characters can be digits or a combination of digits and a character such as an asterisk (*) or a pound sign (#). If you use a character, you must position this character first in the FAC.
The asterisk (*) and pound sign (#) characters are often used in pairs. You can use one of these characters and digits to activate a feature and the other character and the same digits to deactivate the feature. For example, if you use the asterisk (*) and the digits 2 and 9 to activate the Posted Messages feature, then you can use the pound sign (#) character and the digits 2 and 9 to deactivate the Posted Messages feature.
In practical terms, the implementation is identical, but there may be specific FFCs that do not have a corresponding FAC and vice versa.
