What is the IEC 11801 Cable Code Designation ( U/UTP, S/UTP, U/FTP..)?








U/UTP: UNSHIELDED TWISTED PAIRS

Also known as UTP, this is currently the most common and basic method of cable construction, consisting of pairs of wires twisted together. There is no shielding, instead the symmetrical twist in the wires create a balanced transmission line, helping to reduce electrical noise and EMI. In addition, the different twist rates of each pair can be used to reduce crosstalk. In higher category cables, a cross-web filler may be found separating the individual pairs to help reduce alien crosstalk from adjacent cables.


F/UTP: FOILED WITH UNSHIELDED TWISTED PAIRS.

Often referred to as FTP, this type of cable features an overall foil shield wrapped around unshielded twisted pairs and a drain wire. When the drain wire is correctly connected, unwanted noise is redirected to ground, offering extra protection against EMI/RFI.


S/UTP: SHIELDED WITH UNSHIELDED TWISTED PAIRS.

This cable construction has an overall braid screen with unshielded twisted pairs. This cable is often referred to as an STP, however this term should be used with caution due to other shielded cables also using this term. Always check whether the cable will have any shielding and whether individual pairs have their own shield. The cable is capable of supporting higher transmission rates across longer distances than U/UTP and provides better mechanical strength and grounding due to the braid.


SF/UTP: SHIELDED AND FOILED WITH UNSHIELDED TWISTED PAIRS.

This cable has both an overall braid shield and foil shield with unshielded twisted pairs. This cable offers effective protection from EMI both from the cable and into the cable as well as much better grounding due to the additional braid.



U/FTP: UNSHIELDED WITH FOILED TWISTED PAIRS

This type of cable has no overall shielding but the individual twisted pairs are wrapped in a foil screen, offering some protection from EMI and crosstalk from adjacent pairs and other cables.

F/FTP: FOILED WITH FOILED TWISTED PAIRS

This type of cable features an overall foil shield with individually foil tape shielded twisted pairs. These are similar to F/UTP cables, with the addition of a foil shield around each twisted pair. The cable construction is designed to provide the assembly with greater protection from crosstalk from adjacent pairs and other cables, RFI and EMI.

S/FTP: SHIELDED WITH FOILED TWISTED PAIRS

Similar to F/FTP, the individual twisted pairs are wrapped in a foil tape before being wrapped in an overall flexible yet mechanically strong braid screen. The additional foil on the twisted pairs helps to reduce crosstalk from adjacent pairs and other cables. The braid provides better grounding.


SF/FTP: SHIELDED AND FOILED WITH FOILED TWISTED PAIRS

Offering the maximum protection from RFI/EMI, crosstalk and alien crosstalk, this cable has both an overall braid shield and foil shield, with individually foil tape screened twisted pairs. This type of cable provides the best level of protection from interference and better grounding due to the braid.

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Common Cable Designations

1. U/UTP
Meaning: Unshielded cable.
U: No overall shielding.
UTP: No shielding around the twisted pairs.
Construction: Completely unshielded cable with twisted pairs.
Applications: Low-interference environments (e.g., homes, small offices).
Example: Standard Ethernet cables (Cat 5e).

2. F/UTP
Meaning: Foil-shielded cable with unshielded pairs.
F: Foil shielding around the entire cable.
UTP: No shielding around the individual twisted pairs.
Construction: Overall foil shielding protects against external interference, but individual pairs are unshielded.
Applications: Areas with moderate electromagnetic interference (EMI).

3. S/FTP
Meaning: Braided shielding for the overall cable and foil shielding for individual pairs.
S: Braided metal shielding around the entire cable.
FTP: Foil shielding around each twisted pair.
Construction: Provides excellent EMI protection for both the cable and each pair.
Applications: High-EMI environments, such as industrial setups or data centers.

4. SF/UTP
Meaning: Combination of braided and foil shielding for the entire cable.
SF: Both foil and braided shielding for the overall cable.
UTP: Unshielded twisted pairs inside.
Construction: Heavy external shielding with unshielded pairs.
Applications: Environments with significant EMI but less concern for crosstalk.

5. U/FTP
Meaning: No overall shielding but foil shielding for individual pairs.
U: No shielding around the entire cable.
FTP: Foil shielding around each twisted pair.
Construction: Protects against crosstalk but lacks external EMI shielding.
Applications: Balanced environments with moderate crosstalk concerns.

Comparison Table

Designation    Overall Shielding    Pair Shielding    Typical Applications
U/UTP    None    None    Low-EMI environments (homes, basic office setups).
F/UTP    Foil    None    Moderate EMI areas (commercial buildings).
S/FTP    Braided Shielding    Foil    High-EMI environments (data centers, industrial setups).
SF/UTP    Foil + Braided Shielding    None    High EMI with less concern for crosstalk.
U/FTP    None    Foil    Environments requiring crosstalk protection.



Applications of Shielded vs. Unshielded Cables

Unshielded (U/UTP):
Cost-effective.
Lightweight and flexible.
Suitable for low-EMI areas.

Shielded (F/UTP, S/FTP, etc.):
Better protection against EMI.
Ideal for industrial and high-speed data applications.
Requires proper grounding for effective shielding.

Common Use Cases
Cat 5e U/UTP: General-purpose Ethernet connections.
Cat 6A S/FTP: High-speed Ethernet in high-interference environments.
Cat 7 SF/FTP: Ultra-high-speed connections requiring robust EMI protection.