SC or LC: Which Fiber Optic Connector to Choose for a Patch Cord, SFP Module or Optical Box
SC or LC: Which Fiber Optic Connector to Choose for a Patch Cord, SFP Module or Optical Box

When choosing a fiber optic patch cord, pigtail, adapter or SFP module, it is important to correctly identify the type of fiber optic connector. The most common connectors used in modern fiber optic networks are SC and LC. They differ in size, design, application and compatibility with equipment.

In practice, customers often confuse SC and LC, especially when choosing a patch cord for an optical box, media converter, SFP module, patch panel or outdoor fiber optic line. If the wrong connector is selected, the cable simply will not fit the equipment or adapter.

In this article, we will explain the difference between SC and LC, when to choose SC-SC, LC-LC or SC-LC, which connector is more often used in PON/GPON/FTTH, and which one is typically used in SFP modules and network equipment.

What Is a Fiber Optic Connector

A fiber optic connector is the connector at the end of a fiber optic cable, patch cord or pigtail that connects the fiber to equipment, an adapter, optical box or patch panel.

Through the optical connector, the light signal passes from one network component to another. That is why the connector type, polishing type, fiber type and patch cord construction must match the equipment.

When choosing, consider:

  • connector type — SC, LC, FC or ST;
  • polishing type — UPC or APC;
  • fiber type — Singlemode or Multimode;
  • number of fibers — Simplex or Duplex;
  • patch cord length;
  • type of equipment to be connected;
  • compatibility with an adapter, optical box or patch panel.

SC and LC in Simple Words

SC is a larger fiber optic connector with convenient direct connection. It is often used in optical boxes, PON/GPON/FTTH networks, patch panels, media converters and subscriber connections.

LC is a more compact fiber optic connector. It is often used in SFP modules, media converters, server and telecommunication equipment where high port density is important.

Connector Feature Where It Is Most Often Used
SC Larger connector with convenient connection PON/GPON/FTTH, optical boxes, patch panels, media converters
LC Compact connector of smaller size SFP modules, media converters, equipment with high port density

What Is an SC Connector

SC is one of the most common types of fiber optic connectors. It has a rectangular body and uses a push-pull connection: the connector is inserted into the adapter until it locks.

SC connectors are popular because they are easy to install, convenient to connect and widely compatible with optical boxes, patch panels, media converters and subscriber equipment.

SC should be chosen if:

  • SC adapters are installed in the optical box;
  • a patch cord is needed for PON/GPON/FTTH;
  • SC/UPC or SC/APC connection is used;
  • a convenient and widely used connector is required;
  • the equipment has an SC port;
  • an outdoor SC-SC fiber optic patch cord is needed.

What Is an LC Connector

LC is a compact fiber optic connector of smaller size. It is often used where many optical ports need to be placed in a small area.

LC connectors are widely used in SFP modules, optical ports of active equipment, media converters and telecommunication systems. Due to its smaller size, LC allows a more compact connection layout.

LC should be chosen if:

  • the SFP module has an LC port;
  • the media converter or equipment uses LC;
  • a compact fiber optic patch cord is needed;
  • LC adapters are installed in the patch panel;
  • a Duplex connection is required for transmit and receive;
  • LC/UPC or LC/APC is specified in the technical requirements.

SC or LC: Main Differences

Parameter SC LC
Size Larger More compact
Connection Push-pull, simple insertion Latch locking
Where it is more often used Optical boxes, PON/GPON, FTTH, patch panels SFP modules, media converters, active equipment
Port density Lower Higher due to compact size
Typical variants SC/UPC, SC/APC, SC-SC, SC-LC LC/UPC, LC/APC, LC-LC, SC-LC

In simple terms: SC is more often used in optical boxes, PON/GPON and subscriber networks, while LC is more often used in SFP modules and equipment with compact optical ports.

SC-SC, LC-LC or SC-LC: What to Choose

A fiber optic patch cord can have the same connectors on both ends or different connectors. The choice depends on which ports are installed on the equipment at both ends of the line.

Patch Cord Type Meaning When to Choose
SC-SC SC connector on both ends For optical boxes, patch panels, PON/GPON, FTTH
LC-LC LC connector on both ends For SFP modules, media converters, equipment with LC ports
SC-LC SC on one end, LC on the other When an SC optical box or patch panel needs to be connected to an LC port of an SFP module

Before buying, check both connection points. For example, if an SC adapter is installed in the optical box and the SFP module has an LC port, an SC-LC patch cord is required.

SC/UPC, SC/APC, LC/UPC, LC/APC: Do Not Confuse Connector and Polishing

SC and LC are connector types, while UPC and APC are connector polishing types. These are different characteristics that should be considered separately.

For example, there can be:

  • SC/UPC — SC connector with blue UPC polishing;
  • SC/APC — SC connector with green APC polishing;
  • LC/UPC — LC connector with blue UPC polishing;
  • LC/APC — LC connector with green APC polishing.

If you have a green APC adapter, you need an APC connector. If you have a blue UPC adapter, you need to use UPC. More details are available in the article UPC or APC: What Is the Difference Between Blue and Green Fiber Optic Connectors.

What to Choose for PON, GPON and FTTH

In PON, GPON and FTTH networks, SC connectors are very often used, especially SC/APC. This is because SC is convenient for subscriber connections, optical boxes, splitters and distribution networks.

For PON/GPON/FTTH, the following are often used:

  • SC/APC patch cords;
  • SC/APC pigtails;
  • SC/APC adapters;
  • optical boxes with SC adapters;
  • outdoor SC-SC patch cords;
  • subscriber FTTH solutions.

However, this does not mean that LC is not used in fiber optic networks. If the equipment has an LC port, you need to choose LC or a combined SC-LC patch cord.

What to Choose for an SFP Module

LC connectors are most often used for connecting to SFP modules. Many SFP modules have LC ports, so LC-LC or SC-LC patch cords are selected for them.

Before choosing a patch cord for an SFP module, check:

  • which connector the SFP module has — LC or SC;
  • whether singlemode or multimode fiber is required;
  • whether Simplex or Duplex is used;
  • whether UPC or APC is needed;
  • what patch cord length is required;
  • which connector is installed at the other end of the line.

The most common situation is when the SFP module has an LC port, while the optical box or patch panel has an SC adapter. In this case, an SC-LC patch cord is needed.

What to Choose for a Media Converter

Media converters can have different types of optical ports. Some models use SC, others use LC or an SFP slot where a separate SFP module is installed.

Before buying a patch cord for a media converter, check:

  • whether the media converter has a built-in SC or LC port;
  • whether an SFP module is used;
  • what fiber type is required;
  • what polishing type is required;
  • which connector is on the other end of the line;
  • what cable length is needed.

If the media converter has an SC port, an SC patch cord is required. If an SFP module with an LC port is used, an LC or SC-LC patch cord is needed depending on the second connection point.

What to Choose for an Optical Box or Patch Panel

Optical boxes and patch panels usually already have adapters installed. Patch cords and pigtails should be selected according to these adapters.

Before buying, check:

  • which adapter type is installed — SC or LC;
  • what color the adapter is — blue or green;
  • which polishing type is needed — UPC or APC;
  • whether Simplex or Duplex is used;
  • whether singlemode or multimode fiber is required;
  • whether an indoor or outdoor patch cord is needed.

If SC/APC adapters are installed in the box, SC/APC patch cords or pigtails should be used. If LC/UPC adapters are installed in the patch panel, LC/UPC components are required.

Simplex or Duplex: How It Relates to SC and LC

SC and LC can be used in both Simplex and Duplex versions.

Construction Meaning When It Is Used
Simplex One fiber PON/GPON, FTTH, BiDi connections, subscriber lines
Duplex Two fibers Transmit and receive work through separate fibers

For example, SC/APC Simplex is often used in PON/GPON and FTTH. LC/UPC Duplex is often used for SFP modules, where one connector is responsible for transmission and the other for receiving the signal.

Singlemode or Multimode: Does It Depend on SC or LC?

The SC or LC connector type does not determine the fiber type. Both SC and LC can be used with singlemode or multimode fiber.

That means a patch cord can be:

  • SC-SC Singlemode;
  • LC-LC Singlemode;
  • SC-LC Singlemode;
  • LC-LC Multimode OM3;
  • SC-SC Multimode;
  • SC/APC G.657.A1;
  • LC/UPC G.652D.

For long distances and PON/GPON, singlemode fiber is usually used. For short connections in server rooms and data centers, multimode OM3 or OM4 fiber can be used if required by the equipment.

SC or LC for an Outdoor Fiber Optic Patch Cord

For outdoor fiber optic patch cords, the choice between SC and LC depends on the equipment that needs to be connected.

SC-SC is often used for:

  • FTTH / PON / GPON;
  • optical boxes;
  • subscriber connections;
  • outdoor cabinets;
  • simple connection between SC adapters.

LC-LC or SC-LC is often used for:

  • SFP modules;
  • media converters with LC ports;
  • connecting active equipment;
  • connecting an SC optical box to an LC port of equipment.

If you are not sure which patch cord is needed, check the ports on both sides. They determine whether SC-SC, LC-LC or SC-LC is required.

How Not to Make a Mistake When Choosing SC or LC

Before buying a fiber optic patch cord, pigtail or adapter, check not only the connector type but the full combination of parameters.

Pay attention to:

  • connector type on the first side — SC or LC;
  • connector type on the second side — SC or LC;
  • polishing type — UPC or APC;
  • fiber type — Singlemode or Multimode;
  • fiber standard — G.652D, G.657.A1, G.657.A2, OM3, OM4;
  • Simplex or Duplex;
  • patch cord length;
  • outdoor or indoor design;
  • compatibility with equipment.

The simplest rule is to first check which port or adapter is already installed, and then choose a patch cord for it.

Common Mistakes When Choosing SC and LC

  • buying an SC patch cord for equipment with an LC port;
  • choosing LC-LC when SC is needed on one side;
  • confusing connector type with polishing type;
  • buying SC/UPC instead of SC/APC;
  • not checking whether Simplex or Duplex is needed;
  • not considering fiber type — Singlemode or Multimode;
  • choosing only by connector color;
  • not checking SFP module or media converter ports;
  • choosing a patch cord only by length;
  • not considering that different connectors may be needed on both ends.

Most mistakes happen when the customer looks only at the cable length but does not check the connector type, polishing type and equipment.

What Products Are Bought Together with SC and LC Patch Cords

For correct optical line connection, the following products are often ordered together with SC or LC patch cords:

The main rule is that all components of one line must be compatible with each other: connector type, polishing type, fiber type, number of fibers and cable length.

FAQ

What Is SC in Fiber Optics?

SC is a common type of fiber optic connector with a rectangular body and convenient push-pull connection. It is often used in optical boxes, PON/GPON/FTTH, patch panels and media converters.

What Is LC in Fiber Optics?

LC is a compact fiber optic connector of smaller size. It is often used in SFP modules, media converters and equipment with high port density.

Which Is Better: SC or LC?

One connector is not always better than the other. SC is more often used for PON/GPON, FTTH, optical boxes and patch panels. LC is more often needed for SFP modules and compact equipment.

Can SC Be Connected to LC?

Yes. For this, an SC-LC patch cord is used. It has an SC connector on one side and an LC connector on the other. This option is needed when equipment on both ends has different ports.

What Should I Choose for an SFP Module — SC or LC?

Most SFP modules use an LC port, so LC-LC or SC-LC patch cords are often required. But before buying, check the specifications of the specific SFP module.

What Should I Choose for GPON — SC or LC?

In GPON and FTTH, SC is very often used, especially SC/APC. But always check which adapters and ports are already installed in the network.

Does UPC or APC Depend on SC or LC?

No. SC and LC are connector types, while UPC and APC are polishing types. There can be SC/UPC, SC/APC, LC/UPC or LC/APC.

How Do I Know Which Patch Cord I Need?

Check the ports on both sides: on the equipment, optical box, patch panel or SFP module. It is also important to consider UPC/APC, Singlemode/Multimode, Simplex/Duplex and the required length.

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Conclusion

SC and LC are two of the most common fiber optic connector types. SC is larger and is often used in PON/GPON/FTTH, optical boxes, patch panels and subscriber connections. LC is more compact and is often used in SFP modules, media converters and equipment with high port density.

To choose the right fiber optic patch cord, check the ports on both ends of the line. If both ends use SC, an SC-SC patch cord is needed. If both ends use LC, an LC-LC patch cord is needed. If one side uses SC and the other uses LC, an SC-LC patch cord is required.

It is also important not to confuse connector type with polishing type. SC or LC connectors can be UPC or APC, singlemode or multimode, Simplex or Duplex. Choosing all parameters correctly helps avoid unnecessary signal loss, incompatibility and buying the wrong cable again.

Need help choosing an SC or LC patch cord? Net-Server specialists will help you choose an SC-SC, LC-LC, SC-LC, UPC or APC patch cord, pigtail, adapter, optical box or other components for your fiber optic network.