EXFO FTB-8500 Series for FTB-500 - Manual (Page 74)

Introducing the Smart User Interface
60 FTB-8500 Series and FTB-8120NGE/8130NGE
Keyboard Usage

Numerical keyboards: Allows entering integer/decimal values.

For integer unsigned or signed values
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For rate values: Allows entering the rate values (0 through 9, and
exponent)
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For IP address, Subnet Mask and Default Gateway values