In the intricate web of modern communication networks, patch cords effectively ensure seamless connections between devices and systems. They play a pivotal role in delivering data, voice, and video signals across various platforms. In this article, we will explore the world of patch cord types, shedding light on their significance, main categories.
Understanding Patch Cord
A patch cord is a short, flexible cable with connectors at both ends, designed to establish quick and secure connections between electronic devices. It is crucial for transmitting data, voice, and video signals in modern communication networks.
Fiber optic patch cords can be classified based on the following criteria:
- Optical Signals Type: Depending on the type of optical signals they transmit, fiber optic patch cord can be divided into single-mode and multi-mode. Single-mode patch cords are suitable for long-distance applications, while multi-mode patch cords are used for shorter distances.
- Connector Type: Different connectors are used, such as SC, LC, ST, and MPO/MTP, to suit specific network requirements and devices.
- Numbers of Fiber Strands: Patch cords can have a single fiber (simplex) or multiple fibers (duplex) for bidirectional communication.
- Polishing Type: According to this type, fiber optic patch cord can be divided into Physical contact, ultra physical contact and angled physical contact.
These classifications help ensure that the right fiber optic patch cord is selected to meet the specific needs of a given application or network. In the following paragraph, we will introduce in detail the differences between patch cords according to these classifications.
Type of Optical Signals
Single Mode Fiber(SM)
Generally, the color of single-mode fiber patch is yellow, and the connectors and protective sleeves are blue. Its diameter is usually 8-10 microns and the cladding diameter is 125µm. The fiber core is very small, and it only allows one type of light to pass through the slender fiber core. This results in light having almost no reflection during transmission and propagating in one mode. The light propagates farther, so single-mode fiber is more suitable for long-distance transmission while minimizing signal loss or attenuation.
Single-mode fiber comes in two variants, known as OS1 and OS2 (OS stands for Optical Single-mode), which differ in their structure and intended use. When comparing OS1 and OS2 single-mode fiber cables, it becomes evident that both are suitable for long-distance data transmission. However, OS2, with its superior performance and lower signal losses, is particularly well-suited for demanding long-haul data transmission applications.
For a detailed introduction and comparison between OS1 and OS2, you can click here to view our other article.
Multimode Optical Fiber(MM)
Multimode optical fiber is capable of accommodating various light modes on a single fiber strand. However, due to the multiple light paths it supports, the range of multimode fiber jumpers is generally limited, making them most suitable for short to medium distances and lower-capacity optical fiber communication systems. For short-distance data transmission within buildings or campuses, multimode fiber patch cords are the preferred choice.
They typically feature a core diameter of 50 or 62.5µm and a cladding diameter of 125µm. Sometimes, this specification is denoted as core/cladding diameter, such as 50/125µm or 62.5/125µm.
Multimode fiber comes in five variants, each designed to support specific transmission rates or distances, including 62.5-micron OM1, 50-micron OM2, 50-micron OM3, 50-micron OM4, and 50-micron OM5 (OM stands for Optical Multi-mode). These variants are distinguishable by their standardized jacket colors.
For a detailed introduction and comparison of OM1, OM2, OM3, OM4 and OM5, you can click here to view our other article.
Number of Fiber Strands
Simplex Fiber Patch Cord
A simplex fiber patch cord is a streamlined solution, comprising a single fiber strand with a simplex connector at each end. This configuration is ideal for scenarios requiring a one-to-one connection. Simplex patch cords are commonly paired with Bi-Directional (BiDi) transceiver modules, which feature just one port, making them an efficient choice for scenarios where compactness and efficiency are paramount.
Duplex Fiber Patch Cord
In contrast, a duplex fiber patch cord consists of not one, but two strands of glass or plastic fibers, each equipped with its own connector, typically forming a duplex connector or considered as two simplex connectors. This configuration facilitates bidirectional communication, allowing data to flow in both directions simultaneously. Duplex patch cords are versatile and compatible with a wide range of common transceivers or dual fiber BiDi transceivers, making them suitable for applications where data transmission in both directions is essential.
Simplex patch cords simplify unidirectional connections, whereas duplex patch cords, with their bidirectional capability, offer increased flexibility for applications where data must travel in both directions.
Connector Types of Patch Cord
Common connector types of fiber optic patch cords include FC, SC, ST, and LC. Fiber optic jumpers with FC connectors are mostly used on distribution frames, while fiber jumpers with SC connectors are mostly used on router switches. In addition, there are various fiber connector types such as MTRJ, MPO, MU, SMA, FDDI, E2000, D4, etc.
Following are detailed introduction for the connectors we’ve metioned:
1. FC: Ferrule Connector
The FC patch cord connector finds common application in telecommunications networks, where it offers reliable and dust-proof performance. However, one downside to this connector is that it may require slightly longer installation times. FC connectors are typically employed on the ODF side, often utilized on patch panels and optical transceivers for efficient network connectivity.
2. SC: Subscriber Connector
SC is a connector commonly used to link with GBIC optical modules. It features a rectangular shell and employs a straightforward plug-and-latch mechanism, eliminating the need for rotation during installation. The SC connector’s direct plug-and-play design offers convenience in usage, but it may have a drawback of being more prone to unintentional disconnection. This connector is frequently found in routers and switches, where its simplicity serves well in various network applications.
3. ST: Straight Tip Connector
Upon insertion, the ST connector is secured by rotating it half a circle and locking it in place with a bayonet mechanism. However, a potential drawback is its susceptibility to breakage. ST connectors are commonly found in optical fiber distribution frames, characterized by a round shell and fastened with a screw buckle. In 10Base-F connections, the ST connector type is typically the preferred choice.
4. LC: Lucent Connector
Connector to the SFP module, which is made with an easy-to-operate modular jack (RJ) latching mechanism. (SFP optical module defaults to LC interface)
5. MTRJ: Mechanical Transfer Registered Jack
The MTRJ fiber optic jumper is a square-shaped connector with an integrated transceiver and a dual-fiber transceiver on one end. This jumper comprises two precision plastic molded connectors and an optical cable. The connectors feature precision plastic components and incorporate a push-pull plug-in clamping mechanism. MTRJ jumpers are well-suited for indoor applications within telecommunications and data network systems, providing reliable connectivity in various network setups.
6. MPO: Multi-Fiber Push-On Connector
The MPO patch cord connector is a multi-core, multi-channel plug known for its rectangular ferrule with a nominal diameter of 6.4mm × 2.5mm. It aligns with guide pins through left and right guide holes, allowing it to connect 2 to 12 core optical fibers side by side, or up to two rows of 24 core fibers at once. A spring at the end of the ferrule applies pressure for docking until the connector locks with the adapter. The upper side features a male key that ensures proper fiber alignment during connection.
7. MU: Miniature Unit Coupling
The world’s smallest single-core optical fiber connector developed by NTT. The connector uses a 1.25mm diameter sleeve and a self-retaining mechanism. Its advantage is that it is small in size and can achieve high-density installation.
8. SMA: SubMiniature version A
SMA patch cord connectors are used in special occasions in optical fiber communication systems. Such as test equipment, data network, military equipment, medical equipment, etc. SMA connectors mainly have ferrules made of two different materials, one made of ceramic and the other made of metal.
9. FDDI: Fiber Distributed Data Interface
FDDI patch cord connectors is mainly used in duplex fiber optic systems. The fddi backbone and IEEE802.4 token bus comply with the ansi3t95 FDDI pmd specification.
10. E2000: Named after its manufacturer, Diamond E-2000™
The E2000 patch cord connector adopts a push-pull locking setting, which is easy to install. The outer shell is made of engineering plastic, which facilitates dense installation. It is mainly used for single-mode optical fiber. The connector comes with a dust cover.
11. D4: Duplex 4 Connector
The D4 patch cord connector is an older type of connector, with a positioning ring and a pressure control spring, which can avoid damage to the end face due to excessive plugging pressure, so the loss of this device is small. . The pin diameter is 2.0mm. The body of the D4 crimp-type connector is made of nickel-plated brass, and tail sleeves are available in a variety of colors.
PC patch cord connectors utilize microsphere grinding and polishing to create a slightly spherical surface on the ferrule. This design ensures that the fiber core is positioned at the highest point of bending. It result in reduction in the air gap between fiber components, promoting physical contact between the two fiber end faces. This precise contact minimizes signal loss, making PC connectors ideal for applications where low attenuation is critical.
Ultra Physical Contact(UPC)
UPC patch cord connectors take PC technology a step further by optimizing end-face polishing and surface finish. The end face of a UPC connector isn’t entirely flat; instead, it features a slight arc, achieving a more precise docking surface. This enhanced polishing technique results in a dome-shaped end face. UPC connectors are well-suited for applications requiring even more precise and low-loss connections.
Angled Physical Contact(APC)
APC patch cord connectors take a different approach by grinding the fiber end faces to an 8° bevel. This beveled angle not only brings the fiber end faces closer together but also reflects light through the bevel angle to the cladding rather than directing it straight back to the light source. This design provides superior connection performance by reducing back reflections and ensuring a more stable connection.
Distinguish Fiber Optic Cable and Connector Colors
Different fiber optic cords are also distinguished by different colors, which allows us to quickly distinguish the type. Of course, the color of fiber optic cords can be customized according to customer needs. Most manufacturers will adopt or refer to the TIA-598 standard. Therefore, we can distinguish the type of fiber optic patch cord by looking at the color of the fiber optic cable and the color of the connectors.
The Color of Fiber Optic Cable Jacket
Here are some common color codes used to distinguish various types of patch cords:
Single-Mode Patch Cords
Yellow: Typically used for single-mode patch cords with UPC or PC connectors.
Blue: Less common but occasionally used for single-mode APC connectors.
Multi-Mode Patch Cords
Orange: Commonly used for multi-mode patch cords like OM1, OM2.
Aqua: Often used for multi-mode patch cords with laser-optimized OM3 or OM4(OM4 is usually purple in European regions) fibers.
Lime Green: Used for patch cords with OM5 wideband multi-mode fibers.
Colors of connectors
Because fiber optic connectors are polished differently, fiber optic color coding is often used to differentiate between fiber optic connector types. However, metal fiber optic connectors such as FC and ST cannot be color-identified, so some suppliers use special leather covers for marking. For example, some suppliers use black leather covers for ST fiber optic connectors. The color of the holsters used by different suppliers may vary.
Here are the common color codes for these connectors:
Blue: Single-mode connectors are typically identified by a blue color, which signifies their compatibility with single-mode optical fibers.
Beige or Beige with Black: Multi-mode connectors are commonly beige or beige with black for traditional multi-mode optical fibers, such as OM1 and OM2.
Aqua: For multi-mode connectors designed for laser-optimized multi-mode fibers, particularly OM3 and OM4, the color aqua is used.
Moreover, according to EIA/TIA-598, multi-core fiber patch cords follow specific color-coding rules. For up to 12 fibers, each is assigned a unique color, like the first being blue and the second, orange. When the core count exceeds 12, the initial twelve colors are reused. To differentiate, additional colors, like a blue jacket with black stripes, are employed for the extra fibers.
Know More About Fiber Optical Cable: The Material
We often see parameter labels printed on optical cables. Among them, LSZH and PVC refer to the material of the cable.
PVC (Polyvinyl Chloride):
PVC cables contain halogen, specifically chlorine, which will produce harmful gases when burning. Thus it poses a concern when it comes to fire safety, making them unsuitable for indoor applications where the safety and health of occupants are a priority. However, PVC cables exhibit robust mechanical properties, rendering them a cost-effective choice for applications with less stringent requirements.
LSZH (Low Smoke Zero Halogen):
Conversely, LSZH cables are crafted from a low-smoke, halogen-free material, prioritizing both environmental safety and flame retardance. These cables emit minimal smoke and do not produce toxic halogen gases when exposed to fire, making them a preferred choice for indoor installations, particularly in locations where safety and air quality are paramount. While LSZH cables excel in terms of environmental friendliness and flame resistance, they may have slightly inferior mechanical properties compared to PVC cables, and they tend to be more expensive.
Therefore, when selecting fiber optic cables, you need to pay special attention to the materials marked on the cables. Make the choice that suits you best based on the actual situation.
In addition to the material, other relevant data is usually printed on the cable. Common data and their meanings are as follows:
OPTICAL CABLE SM G657A1 FIBER 3.0mm LSZH XX/XX XXXXM
OPTICAL CABLE: Optical fiber cable name
SM: Single mode (may also be OM1, OM2, OM3, OM4, OM5)
G657A1 FIBER: fiber type (may also be G652D; G657A2)
3.0 mm: Optical cable diameter (may also be 0.9mm; 2.0mm)
LSZH: Low smoke, halogen-free (may also be PVC, TPU)
XX/XX: production date
XXXXM: Corresponding number of meters
In addition, at Zion Communication, we will list all the requirements to facilitate customers to choose suitable patch cords according to their needs.
In conclusion, understanding the various types of fiber optic patch cords is essential in today’s interconnected world, where seamless data transmission is a critical component of our daily lives and businesses. By exploring the four classification methods, as well as the difference of color-coding and cable materials, we gain a comprehensive understanding of how to choose the right patch cord for specific applications. Whether it’s the distinction between single-mode and multi-mode fibers, connector types, or cable materials like LSZH and PVC, the knowledge provided in this article empowers us to make informed decisions when it comes to building reliable and efficient optical networks.