EXFO FTB-8500 Series for FTB-500 - Manual (Page 77)

Introducing the Smart User Interface
Ethernet and Fibre Channel Application 63
Keyboard Usage

Full keyboard: Allows entering numbers, letters and some other
characters. The Back, Del, Shift and space bar keys have the same
functionality as a regular PC keyboard.

Trace message keyboard (WAN): Allows entering alphanumerical
characters (ITU T.50) required for J0 and J1 Trace fields. Press the
Ctrl Char button to access these characters.