Reference · Glossary · 18 Terms
Glossary: D
Outside plant terms that start with D, in plain language, with links to the OSP map and the operations steps.
Dark Fiber
Installed fiber that is not lit by electronics. Spare fibers are dark until they are assigned.
Daylighting
Another word for potholing: exposing a utility so you can see it and measure it.
- On the Map: Pothole
- SOP Step: UG-04 Potholing (Daylighting)
- See Also: Potholing
Dead Zone
Also Called: Event Dead Zone · Attenuation Dead Zone
The length after a strong reflection where the OTDR cannot separate or measure events. A launch cable moves the first connector past it.
- On the Map: OTDR with Launch Cable
- SOP Step: SPL-11 Testing and Acceptance
- See Also: OTDR, Launch Cable, Reflective Event
Dead-End
Also Called: Strand Dead-End · Terminal Pole
Where a strand terminates at a pole, usually with a preformed dead-end, guyed against the pull of the line.
- On the Map: Strand Dead-End
- SOP Step: AE-08 Strand Placement and Tensioning
- See Also: Down Guy, Messenger, Longitudinal Load
Distribution
Also Called: Distribution Fiber
Fiber from a cabinet or splice point toward customers, ending at terminals where drops connect.
Down Guy
Also Called: Guy · Guy Wire
Steel strand from a pole to a ground anchor that balances the unbalanced pull of the line.
- On the Map: Down Guy
- SOP Step: AE-07 Down Guys and Guy Guards
- See Also: Anchor, Guy Guard, Preformed Guy Grip, Transverse Load, Longitudinal Load
Drill Head
Also Called: Bit · Bore Head · Duckbill
The slant-faced bit at the front of the drill string, with a housing for the sonde. Pushing without rotation steers it toward the slant face.
- On the Map: Drill Head and Sonde
- SOP Step: UG-06 Pilot Bore and Tracking
- See Also: Sonde, Roll
Drill Rig
Also Called: HDD Rig · Directional Drill
The directional drill that pushes and rotates the rods. It is anchored per the manufacturer and set up with electrical strike protection per the rig manufacturer.
- On the Map: HDD Rig
- SOP Step: UG-05 Bore Planning and Rig Setup
- See Also: Electrical Strike, Drill Rod
Drill Rod
Also Called: Drill Pipe · Drill Stem
One length of drill pipe. Rods are added one at a time, and each rod is a natural interval for a locator reading.
- On the Map: Drill Rods
- SOP Step: UG-06 Pilot Bore and Tracking
- See Also: Bore Log, Pilot Bore
Drilling Fluid
Also Called: Drilling Mud · Bentonite · Slurry
A mix of water and additives, often bentonite, that cools the bit, carries cuttings out and holds the hole open. It is contained at both pits and disposed of per local rules.
- On the Map: Drilling Fluid and Recovery
- SOP Steps: UG-05 Bore Planning and Rig Setup, UG-12 Restoration and Cleanup
- See Also: Frac-Out, Entry Pit
Drip Loop
A downward loop in a drop or riser cable just before it enters a building or fitting, so water runs off the low point instead of following the cable inside.
- On the Map: Aerial Drop
- SOP Step: AE-11 Terminal Coils, Closures, Drops and Risers
- See Also: Aerial Drop, Drop Clamp
Drop
Also Called: Service Drop · Drop Cable
The cable from a terminal or pole to the customer's premises.
- SOP Steps: AE-11 Terminal Coils, Closures, Drops and Risers, UG-11 Cable Placement Underground
- See Also: Aerial Drop, Buried Drop, MST
Drop Clamp
Also Called: Drop Hook
A clamp that holds a drop cable at the pole or at the building's drop hook. A drip loop at the building keeps water from running into the entrance.
- On the Map: Aerial Drop
- SOP Step: AE-11 Terminal Coils, Closures, Drops and Risers
- See Also: Aerial Drop, Drip Loop
Duct
Pipe, usually HDPE or PVC, that houses cable underground. Also called conduit.
- On the Map: HDPE Conduit
- SOP Steps: UG-07 Reaming and Pullback, UG-10 Duct Proving and Pull Tape
- See Also: Conduit, HDPE Conduit, Innerduct
Duct Bank
Also Called: Duct Package
Several ducts placed together in one trench, sometimes encased in concrete.
- On the Map: Duct Bank
- SOP Step: UG-08 Other Placement Methods
- See Also: Duct, Open Trench
Duct Fill
Also Called: Conduit Fill · Fill Ratio · Jam Ratio
The share of a duct's inside area taken up by cables. Fill limits come from the NEC and the owner; a jam check guards against three cables wedging in a pull.
- SOP Step: UG-11 Cable Placement Underground
- See Also: Duct, Innerduct
Duct Proving
Also Called: Proving · Rodding
Pulling a mandrel or test rod, or blowing a rigid proving projectile, each sized per owner spec, through a duct to prove it is clear and round before cable is placed. A foam cleaning plug does not prove a duct.
- On the Map: HDPE Conduit
- SOP Step: UG-10 Duct Proving and Pull Tape
- See Also: Mandrel, Mule Tape
Dynamometer
Also Called: Tension Meter · Dyno
A gauge that reads pulling force. Used to tension strand to the chart and to watch tension during a cable pull.
- SOP Steps: AE-08 Strand Placement and Tensioning, UG-11 Cable Placement Underground
- See Also: Sag, Pulling Tension