Getting to Know FTTx Network

Compared with copper wire, optical fiber’s dominant advantage is the overwhelming information carrying capability, and its high bandwidth and low attenuation easily offset its higher cost. FTTx (fiber to the x) architecture is a typical example of substituting copper by fiber in high data rate traffic. FTTx is a generic term for any broadband network architecture that uses optical fiber to replace all or part of the usual metal local loop used for the last mile telecommunications. The x can be substituted by another letter determined by the delivery topologies that are categorized according to where the fiber terminates. What are the termination places and which letter can be used to substitute x? This article will introduce some FTTx terms.

Different FTTx Architectures

Usually the FTTx items that we are going to introduce are used loosely, as some relate to each other, or just acronyms. Generally the FTTx configurations may fall into two groups: fiber laid all the way to the premises/home/building (FTTP/FTTH/FTTB) and fiber laid to the cabinet/node (FTTC/FTTN), with copper wires completing the connection. Also there are some other FTTx topologies, such as FTTZ (z for zone) and FTTD (d for desktop). The following figure shows simplified schema for four most common FTTx architectures.

FTTx-concepts_and_applications

FTTP: fiber-to-the-premises, is a loosely used term, which can encompass both FTTH and FTTB or sometimes is used a particular fiber network that includes both homes and businesses. It depends on how the context is used and specific location of where the fiber terminates. FTTP can offer higher bandwidth than any other broadband services, so operators usually use this technology to provide triple-play services.

FTTH: as indicated by the name fiber-to-the-home, fiber from the central office reaches the boundary of the living space, such as a box on the outside wall of a home. Once at the subscriber’s living or working space, the signal may be conveyed throughout the space using any means, such as twisted pair, coaxial pair, wireless, power line communication, or optical fiber. Passive optical networks (PONs) and point-to-point Ethernet are architectures that deliver triple play services over FTTH networks directly from a operator’s central office.

FTTB: fiber-to-the-building, -business, or -basement, is very similar to a FTTH. It is a form of fiber-optic communication delivery that necessarily applies only to those properties that contain multiple living or working spaces. The optical fiber terminates before actually reaching the subscribers’ living or working place itself, but does extend to the property containing that living or working place. The signal is conveyed the final distance using any non-optical means, including twisted pair, coaxial pair, wireless, power line communication. FTTB deployment will be the typical for MDU’s and MTU’s (multi-dwelling units and multi-tenant units).

FTTC: fiber-to-the curb or -cabinet, is a telecommunication system where fiber optic cables run directly to a platform near homes or any business environment and serves several customers. Each of these customers has a connection to this platform via coaxial cable or twisted pair. The term “curb” is an abstraction and just as easily means a pole-mounted device or communications closet or shed. Typically any system terminating fiber within 1000 ft (300 m) of the customer premises equipment would be described as FTTC. A perfect deployment example of FTTC is a DLC/NGDLC (digital loop carrier) which provides phone service.

FTTN: fiber-to-the-node or -neighborhood, sometimes identifies and sometimes distinguishes from FTTC. The optical fiber terminates in a cabinet which may be as much as a few miles from the customer premises. Customers typically connect to this cabinet using traditional coaxial cable or twisted pair wiring. The area served by the cabinet is usually less than one mile in radius and can contain several hundred customers. As mentioned before, if the cabinet serves an area of less than 1000 ft (300 m) in radius, the architecture is typically called FTTC/FTTK.

Features of FTTx in LAN Application

Different from a traditional fiber optic network that would be used in local area network (LAN) application, in most FTTx applications, only one optical fiber is used to pass data in two directions. This is very different from the LAN application where the transmit optical fiber sends data in one direction while the receive optical fiber sends data in the other direction. In a LAN application, data transmission over two optical fibers can be simultaneous. However, in an FTTx single optical fiber application, full-duplex operation is typically not possible. Usually half-duplex operation takes place, i.e., part of the time the optical fiber is carrying a signal in one direction and the rest of the time, it is carrying a signal in the other direction. Thus multiple wavelengths are typically used in FTTx systems. The downstream laser is always a different wavelength from the upstream laser. A longer wavelength is used for the former one, such as 1480nm or 1550nm (or both) and typically 1310nm is for the latter one.

Summary

FTTx networks have been acknowledged to be the best choice for phone companies, cities, utilities and commercial service providers to upgrade subscriber connection. Fiber optic cables can carry data at high speeds over long distance while copper cables cannot. The data rate connection is usually limited by the termination equipment rather than the fiber itself, permitting substantial speed improvements by equipment upgrades before the fiber itself must be upgraded. FTTx architecture is being more widely deployed in network applications with its reasonable cost and unlimited performance. FS.COM provides a wide range of FTTx PON components, such as cable distribution and termination accessories, network interface device, PON splitters, etc. For more information you may visit our site or contact sales@fs.com.

Different Ports on WDM Mux/Demux

In the WDM (wavelength-division multiplexing) system, CWDM (coarse wavelength-division multiplexing) and DWDM (dense wavelength-division multiplexing) Mux/Demux (multiplexer/demultiplexer) modules are often deployed to join multiple wavelengths onto a single fiber. Multiplexer is for combining signals together, while demultiplexer is for splitting signals apart. On a WDM Mux/Demux, there are many kinds of ports for different applications. This article will discuss the functions of these ports on WDM Mux/Demux.

WDM Mux/Demux

Necessary Ports on WDM Mux/Demux

Channel port and line port are the necessary ports to support the basic function of WDM Mux/Demux to join or split signals in the data network.

Channel Port

A WDM Mux/Demux usually has several channel ports on different wavelengths. Each channel port works for a specific wavelength. Since there are 18 wavelengths of CWDM ranging from 1270 nm to 1610 nm with a 20nm interval, the number of channel ports on CWDM Mux/Demux also ranges from 2 to 18. DWDM has a more dense wavelength spacing of 0.8 nm (100 GHz) or 0.4 nm (50 GHz) ranging from S-Band to L-Band around 1490 nm to 1610 nm. The number of DWDM Mux/Demux channel ports is about 4 to 96 for high-density networks.

Line Port

Each WDM Mux/Demux will have a line port connecting to the network backbone. Combined channels are transmitted or received at the line port. In addition, line port can be divided into dual-fiber and single-fiber types. Dual-fiber line port is used for bidirectional transmission, therefore the transmit and receive port in each duplex channel must support the same wavelength. However, single-fiber line port only support one direction data flow, thus the transmit and receive port of duplex channel will support different wavelengths. The wavelengths’ order of single-fiber WDM MUX/DEMUX should be reversed at both side of the network.

Special Ports on WDM Mux/Demux

Apart from the necessary ports, some special ports can also be found on WDM Mux/Demux for particular needs.

1310nm Port and 1550nm Port

1310nm and 1550nm ports are certain wavelength ports. Since a lot of optical transceivers use these two wavelengths for long-haul network, adding these two ports when the device does not include these wavelengths is very important. CWDM Mux/Demux can add either type of wavelength ports, but the wavelengths which are 0 to 40 nm higher or lower than 1310 nm or 1550 nm cannot be added to the device. However, DWDM Mux/Demux can only add 1310nm port.

Expansion Port

Expansion port can be added on both CWDM and DWDM Mux/Demux modules. This is a special port to increase the number of available channels carried in the network. That is to say, when a WDM Mux/Demux can not meet all the wavelength needs, it is necessary to use the expansion port to add different wavelengths by connecting to another WDM Mux/Demux’s line port.

Monitor Port

Monitor port is used for signal monitoring or testing. Network administrators will connect this port to the measurement or monitoring equipment to inspect whether the signal is running normally without interrupting the existing network.

ports on WDM mux demux

Conclusion

From this post, we can know that a WDM Mux/Demux has multiple types of ports. Channel and line ports are integral ports for normal operation of the WDM Mux/Demux. 1310nm port, 1510nm port, expansion port and monitor port are used for special requests of the WDM application. Hence, you should have a thorough consideration of your project before choosing the WDM Mux/Demux module.

Functions of ONT and OLT in GPON Network

Gigabit passive optical network (GPON) is a point-to-multipoint access mechanism providing end users with the ability to consolidate multiple services onto a single fiber transport network. To realize this technology, many devices are used to support the network, such as optical splitter, ONT, OLT, etc. In this article, we will mainly discuss the functions of ONT and OLT in GPON network.

GPON

Functions of ONT

Optical network terminal (ONT) is an optical modem that connects to the termination point with an optical cable. It is used at end user’s premise to connect to the PON network on one side and interface with the user on the other side. Data received from the customer end is sent, aggregated and optimized by the ONT to the upstream OLT. ONT is also known as optical network unit (ONU). ONT is an ITU-T term, while ONU is an IEEE term. They both refer to the user side equipment in GPON network. A small difference between them might be the application locations. ONU can work in different temperature and weather conditions.

ONT

Functions of OLT

Optical line terminal (OLT) is the endpoint hardware equipment located in a central office of the PON network. Its basic function is to control the float information in optical distribution network (ODN) to go in both directions. OLT converts the standard signals used by fiber optic service (FiOS) to the frequency and framing used by PON system. In addition, it coordinates the multiplexing between the ONT conversion devices. There are two float directions for OLT system. One is the upstream direction to distribute different types of data and voice traffic from users. The other is the downstream direction which gets data, voice and video traffic from metro network or from a long-haul network and sends it to all ONT modules on the ODN.

OLT

How to Add or Delete ONT on OLT?
Way to Add ONT on OLT

If the password of an ONT is obtained, you can run the ONT add command to add the ONT offline. However, if the password is unknown, you can run the port portid ont-auto-find command in the GPON mode to enable the ONT auto-find function of the GPON port, and then run the ONT confirm command to confirm the ONT. When the ONT is added, you need to run the display ONT info command to see the current status of ONT. If the control flag is active, run state is online, config state is normal, and match state is match, then the ONT adding process is successful.

Way to Delete ONT on OLT

When you need to delete the ONT on OLT, please use the delete command. Then ONT configuration data is deleted with the deletion of the ONT and the online ONT is forced offline. ONT can’t be deleted when it has been configured with other services. You need to unbind the service first before delete the ONT.

How to Troubleshoot ONT?

To troubleshoot the ONT, you should remember that the most important step is to connect your computer directly to the ONT to see if the problem goes away. You can use the Ethernet cable for connection. If the problem still exists, you can reconnect the ONT power supply to clear its internal cache. If the network can not be restored after the above methods, maybe you need to consult professionals for help.

Conclusion

ONT and OLT are indispensable components in the GPON network system. If you are considering to purchase the ONT or OLT devices, FS.COM is a good place to go. Different types of ONT and OLT equipment are provided with high integration, flexible adaption and great reliability to meet all your requirements.

Importance of Plug Boot For RJ45 Cables

Ethernet cables with RJ45 connectors are widely applied to our life. When choosing the RJ45 cables, you may discover that these cables have different appearances of their cable plugs. For example, some cables will have a rubber thing on the clip while some don’t. Why do RJ45 cables have such design and what is the function? This post is going to present the basic knowledge about the special design.

What Is Plug Boot?

This rubber thing is known as plug boot. A booted cable has the plug boot on the cable end of the connector. You can find two main types of boots on the market. One is the separate boot that can be purchased individually to put on the cable, and the other is the injection molded boot to be bought together with the cable. Of course, the latter is more stronger to provide support for the cable when the connector is being pulled out of a switch, patch panel or other devices. Non-booted cables will not have the plug boot as the protection, which are easier to be damaged.

booted cable

Functions of Plug Boot

Generally speaking, the boot design has two purposes. Firstly, the plug boot can prevent the connector clip from flipping up or even breaking off from the cable. When the plastic clip is broken, cable won’t be able to firmly connect to the network which will then interrupt the data transaction. Secondly, using the booted cable is also a protection for your own nails. Because the clip is slim and small, it is easy to stick into the nails during the installation or removal of RJ45 cable. Hence, for the better protection of both cable connector and your nails, Ethernet cables with plug boots are a great solution.

Several Types of Boots

If you want to buy the booted cables, you should also consider which type of boot is best fit for your network since plug boot also has different constructions. Here will introduce the common types of plug boots.

Standard Boot

The standard boot looks like the half of a dome. It protects the clip on all sides and prevents it from snagging or breaking off. This is the type widely applied to cable installation through floors or walls.

standard boot

Molded Boot

Molded boot does not protect the locking clip. It is easy to plug in and out. This type of boot is suitable for hard-to-access space where cables are seldom plugged or unplugged.

molded boot

Snagless Boot

Snagless boot has a small flap to protect the RJ45 clip. It is often used in applications where there are high insertion cycles in easy-to-access space.

snagless boot

Slim Boot

Slim boot has a 28% reduction in diameter than the snagless boot. It offers the minimal protection and is easy to plug or unplug. This type of booted cable is usually seen in high-density applications.

slim boot

No Boot

Non-booted RJ45 cable is much easier for plugging or unplugging, but the whole connector is exposed with no protection. This type is typically used for applications that don’t require frequent unplugging.

no boot

Conclusion

In summary, if you want to have better protection for your Ethernet cables, using plug boots is an ideal solution. If the application does not demand too much cable shifting, non-booted cables are also acceptable. No matter which type of RJ45 cable you choose, the decision must be made according to your own project.

Have You Chosen the Right Power Cord?

Different cables have particular applications. Some are used for data transmission like fiber optic cable or copper cable, and some are used for the transmission of electrical power. Power cord is the assembly widely used as the connection between main electricity supply and the device through a wall socket or extension cord. Power cord is adopted in almost every where when the alternating current power is required. However, have you chosen the right type of power cord for your device? From this article, you may find the answers.

power cord

Overview of Power Cord

A power cord set usually has connectors molded to the cord at each end, thus both ends can detach from the power supply and device. Specifically, power cord assembly consists of three major parts. First is the cable plug, and it is also a male connector used for inserting into the AC outlet to provide power. Then is the receptacle on the other end. Receptacle part is also known as the female connector attached to equipment. Cord is the main section that contains the insulated wires with different lengths and thicknesses.

power cord structure

Common Types of Power Cord

According to different plug and receptacle styles, power cords have different standards. In North America, NEMA power cords and IEC 60320 power cords are the common types with the standards set by NEMA (National Electrical Manufacturers Association) or IEC (International Electrotechnical Commission). Let’s have a look at their differences.

NEMA Power Cord

NEMA power cords have two series of NEMA 5 and NEMA 6. NEMA 5 series is the type widely found in the United States. It has three-wire circuits (hot, neutral, and ground) and is rated to carry a maximum of 125 volts although usually carries about 110 volts and are referred to as “110 circuits”. NEMA 6 series connectors are used for providing heavy duty power to a device. These are typically 208 volt or 240 volt circuits and often referred to as “220 circuits”.

NEMA Power Cord

IEC 60320 Power Cord

The ends of IEC 60320 power cord are on the opposite side of the cord from the power plug. To make it an international standard, the equipment manufacturers need to put one kind of receptacle on their equipment and then manufacture the various country-specific cords when needed. The IEC 60320 C13/C14 connector type is seen on most personal computers and monitors. C19/C20 connector type is used for devices like servers and UPS (Uninterruptible Power Supply) systems.

IEC 60320 power cord

How to Organize Power Cords?

Just like other types of cables, too many power cords can also be easily mixed up during work. Fortunately, there is a simple way to organize the power cords. Instead of labeling all the power cords, you can buy the colored cords for identification. For example, red power cords can be used for important device, and green or blue cords can be used for constantly rearranged equipment. Color coding the system is definitely a more efficient way for cable management.

colorful power cord

Conclusion

The standardization of power cords provides great help for the convenient connectivity when powering different kinds of devices. There is usually a long list of power options for the switch or server. You might be confused when all the components are using the acronyms you don’t know. Therefore, understanding the standards can make the selection of power cords much easier.