Materials Used in Manufacturing of Cords
The following items constitute a telephone instrument
cord. The final requirements of a cable, determine
the items used.
||The typical conductor used for a telephone
instrument cord is called tinsel. In some cases annealed
bare copper is also used
Tinsel is a special type of Drawn Copper
|A 0.079 mm Copper strand is flattened which is called
a ribbon. These ribbons are wound round a yarn to form
Many cores are wound to form a
||The various types of tinsel used are:
1. 4x1 tinsel
2. 4x2 tinsel
3. 7x1 tinsel
4. 7x2 tinsel
Tinsel types used in telephone cords are
Plain Annealed Bare Copper or Cadmium copper
The type of insulation used for a coil cord,
determines many of the cord properties. It is important to
use the correct insulation. The insulated conductor determines
properties as elongation, retraction, coiling, cable break-load,
Some of the types of insulation materials are:
1. Polypropylene - PP
2. Polyethylene - PE
3. Poly Vinyl Chloride - PVC
Sheath on the Cord
The insulated conductors are placed parallel and over sheathed.
The material normally used is PVC. For other applications
materials like Poly Urethane (PU) etc., are used.The material
preferred is based on temperature, area of usage (internal
or external, atmospheric conditions), abrasion requirements,
In most of the countries modular plugs are used as terminations.
The other type of terminations that are in vogue are Y terminals,
Country specific plugs, etc. The modular plugs are inserted
with nickel plated terminals on which gold plating is done.
The gold plating types prevailing in the industry are gold
flash, 03u", 6u”, 15u”, 30u”, 50u”. In Europe, most countries
have their own type of plugs.
In India, for the BSNL phone the 50u” plugs are used.
The modular plugs are FCC approved and are available with
UL 94 V0 and UL 94 V2 requirements.
||Gold Plated Plugs
|Korean Plug-Bottom View
||Korean Plug-Top View
Next - Color Matching in Cable Manufacture.