FIFA
A plug in-unit with built in FIU 19E RRI and E1. Supports 16 asymmetric E1 interfaces.
FIEA
A plug-in-unit that supports 8 E1 Asymmetric (75 ohm) interfaces
FIPA
A plug-in-unit that supports 8 E1/T1 Symmetric (120 ohm for E1, 100 ohm for T1) interfaces
GUI
Graphical User Interface