This white feather-like thing exposed out of telephone cable:

enter image description here
(click on the image to enlarge)

This wire comes from the Main office to my home.

The white "feather" has two copper wires side by side.

What is the name for this feather thing?

  • At first I thought "optical fiber", too, but... that doesn't really make sense for phone cables a normal person would see the insides of. What country are you in, and what type of telephone wire did you split open (i.e. was it the cord connecting the handset to the base station, or the base station to the wall, or your home to the utility box, or...?). Because, at least in the U.S. optical fiber isn't used to connect handsets to base stations, or the base station to the wall. It'd be regular wire in both. Partially because phones still need to use POTS voltages. Aug 15, 2017 at 4:16
  • @ParthianShot I added extra info, does it help you to identify the image?
    – user60476
    Aug 15, 2017 at 4:35

1 Answer 1


It's hard to make out anything in your out-of-focus photo, but I would guess that it is "filler":

Fillers are generally used for three reasons:

  1. To fill gaps in a cable for a more attractive appearance.
  2. To create and maintain a sequence or lay-up of components.
  3. To add strength to a cable.

The above quote is from here:


This link has a nice photo of the cross section of an ethernet cable, which shows the filler:


  • This, especially number three: when one pulls the cabling through walls and across ceilings, the stress is primarily on the filler, not the conductors.
    – Davo
    Aug 15, 2017 at 12:07

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