Before we go on, let's quickly go over some new terminology that was released with the 568-3.D standard, since these terms have been adopted into Fiber OWL 7 series certifiers, including the Fiber OWL 7 BIDI.
In TIA 568 cabling standards, a link type is determined by the type of connection points at the ends of the fiber.
Fiber optic professionals with previous experience may refer to these connection points as distribution frames and cross-connects, and use acronyms such as MDF, MC, IDF, IC, HC, and work area (WA).
A quick list of how these once-familiar terms have been re-defined is provided below.
Now, let's continue.
If one end of the link terminates at an equipment outlet (EO) such as a cubicle or an office, then the link is considered to be a horizontal link, with a designation of CS1 which stands for Cabling Subsystem 1.
However if both ends terminate in a type of telecom closet, then the link is considered to be a backbone link.
CS2 (Cabling Subsystem 2) is a type of backbone that occurs when a Distributor A (HC) is connected either to Distributor C (MC or MDF) or to a Distributor B (IC or IDF).
CS3 is a type of backbone that only occurs when Distributor C (MC or MDF) is connected to a Distributor B (IC or IDF).
Going back to the position of the testers – COMPUTER ROOM to NETWORK HUB 3 – it is safe to assume that this link would be considered a backbone link since both rooms would include patch panels commonly found in distributors.
So, press the right arrow key until the FIBER TYPE field reads 50.0um CS2/3, then press the down arrow to advance to the CONNECTORS field.
Distributor C (DC) = MDF/MC
Distributor B (DB) = IDF/IC
Distributor A (DA) = HC
Equipment Outlet (EO) = work area (WA)
CS1 (Cabling Subsystem 1) = horizontal link which terminates at an EO on one end and any type of distributor on the other end.
CS2 (Cabling Subsystem 2) = backbone link which terminates at a DA on one end and either a DB or DC on the other end.
CS3 (Cabling Subsystem 3) = backbone link which goes between a DC and a DB.