Unlike required Tier 1 testing for attenuation (insertion loss), length and polarity that can be achieved with an optical loss test set (OLTs), few technicians in the field find themselves faced with Tier 2 testing and the need for an Optical Time Domain Reflectometer (OTDR). But every now and then, there is that one customer or consultant who specifies Tier 2 testing—especially as fiber networks have ever-tighter loss budgets and less room for error. Or there may be the need to gain more insight into the performance of a link component for troubleshooting purposes.