POE(Power Over Ethernet)Explained

What Is PoE in Networking?

Power over Ethernet delivers electrical power to PoE-enabled devices using your CATx network cables. Because you don’t need to run electrical wiring, PoE saves money in materials and installation time. It’s also flexible, especially for remote applications, since it doesn’t require a nearby electrical outlet. These and other benefits have led to a sharp increase in PoE’s popularity in recent years. However, the limiting factor has always been power.

How Does PoE Work?

The way it works is simple. Ethernet cable that meets CATx standards consists of four twisted pairs of cable, and PoE sends power over these pairs to PoE-enabled devices. First PoE standards use two twisted pairs to transmit data, while the remaining two pairs are used for power transmission. With the new PoE standards, power and data are both sent over all four twisted pairs.

When the same pairs are used for both power and data, the power and data transmissions don’t interfere with each other. That’s because electricity and data are transported at opposite ends of the frequency spectrum. Electricity has a low frequency of 60 Hz or less, and data transmissions have frequencies that can range from 10 million to 100 million Hz.

What Is the 802.3at PoE Standard?

The original IEEE 802.3af-2003 PoE standard provides up to 15.4 W of DC power on each port. The updated IEEE 802.3at-2009 PoE standard, also known as PoE+ or PoE plus, allows for up to 30 W of power to Type 2 devices. That’s sufficient power for devices such as VoIP phones, wireless access points, and security cameras. But it’s not enough for technology like flat screen displays, LED lighting, or retail POS terminals.

Introducing the 802.3bt PoE Standard

To meet the demand for higher power, the IEEE released a new PoE standard at the end of 2018, to significantly increase capacity. IEEE 802.3bt allows for up to 60 W to 100 W of power at the source by providing power over four pairs of wires (compared to the previous technology’s ability to power over just two pairs). This increase in power allows you to use PoE for a greater range devices and applications. As an added benefit, the new standard will boost energy efficiency by minimizing power loss in the cable, potentially cutting power loss in half.

The new standard will include support for 2.5GBASE-T, 5GBASE-T and 10GBASE-T, while existing standards have a maximum speed of 1-Gbps. This new support will create intermediate data speeds between existing standards.

PoE Types and Power Levels

Previous PoE technology included PoE Type 1, also called IEEE 802.3af, and PoE Type 2, better known as 802.3at or PoE+. Both utilise 2-pair Power over Ethernet, Type 1 with a maximum of 15.4 W per port and Type 2 with a maximum of 30 W per port.

With the new 802.3bt standard come two new options: Type 3 and Type 4. Type 3 is also called 4-pair PoE, 4PPoE, PoE++, or UPoE. It provides 60 W of power per port and is ideal for video conferencing equipment, multi-radio wireless access points, PTZ cameras, and building management devices.

Type 4 (another designation is high-power PoE) offers the highest power capabilities, potentially up to 100 W of DC power (71.3 W to each device), and can support flat screens and laptops. For more detailed specifications on PoE Type 4 and other types, you can refer to the following table.

Name IEEE Standard Power to Powered Device (PD) Max. Power per Port Energized Pairs Supported Devices
PoE IEEE 802.3af 12.95 W 15.4 W 2-pair Static surveillance cameras, VoIP phones, wireless access points
PoE+ IEEE 802.3at 25.5 W 30 W 2-pair PTZ cameras, video IP phones, alarm systems
PoE++ IEEE 802.3bt (Type 3) 51 W 60 W 4-pair Video conferencing equipment, multi-radio wireless access points
PoE++ IEEE 802.3bt (Type 4) 71.3 W 100 W 4-pair Laptops, flat screens


PoE Applications and Benefits

  • Use one set of twisted-pair wires for both data and low-wattage appliances.
  • In addition to the applications noted above, PoE also works well for video surveillance, building management, retail video kiosks, smart signs, vending machines, and retail point-of-information systems.
  • Save money by eliminating the need to run electrical wiring.
  • Easily move an appliance with minimal disruption.
  • If your LAN is protected from power failure by a UPS, the PoE devices connected to your LAN are also protected from power failure.

PoE Ethernet Switches

PoE Ethernet Switches can act as a power source equipment besides their usual functions. They inject power into the Ethernet cable to power the attached PoE-enabled devices such as wireless access points and security cameras. Find out more about PoE Ethernet Switches.

PoE Splitters

PoE Splitters receive a PoE signal with data and power. They separate data and power onto two different lines to support non-PoE devices. Find out more about PoE Splitters.

PoE Repeaters/ PoE Extenders

Enable extension of PoE connections beyond the 100-meter limit to access far away PoE devices such as access points, cameras, and VoIP phones. Find out more about PoE Repeaters / Extenders.

PoE Media Converters

PoE Media Converters are the ideal way to extend your network over fibre or copper and also provide power to remote PoE devices to long-distance data links. They act as a copper to fibre converter and power source equipment all in one device. Find out more about PoE Media Converters.

PoE Injectors

PoE injectors carry data and power simultaneously over a single Ethernet cable. These type of Injectors power various VoIP phones, security system cameras, wireless network access points, Bluetooth® access points, and other 802.3af-compatible equipment. With it, you avoid the cost and hassle of installing AC power at remote cameras, access point, or thin client. Move equipment from room to room without costly, time-consuming rewiring. Find out more about PoE Injectors.


source : https://www.blackbox.nl/

How To Install A New Hard Drive To Replace An Old One

Hard drive space isn’t infinite. Today’s massive drives, with capacities exceeding 1TB, can create that illusion. But as drive sizes increase, ways to consume drive capacity also expand. HD video, for example, can eat gigabytes for breakfast.

That’s the bad news. The good news is that learning how to install a new hard drive isn’t difficult, so there is no need to be concerned about a hard drive that is nearly full.  Read on to find out how to install a new drive to replace an old one.

Identifying The Proper Replacement

Before you can upgrade a hard drive with a new replacement you’ll need to determine the type of drive you need to buy. Today, most hard drives use a data connection known as SATA. However, computers that are several years old might instead support a data connection called IDE. You can easily tell the difference between the two because an IDE connection uses numerous pins, while SATA uses a pin-less L-shaped connector. The picture below provides a comparison – the SATA drive is on the left and the IDE drive is on the right. Laptop drives will obviously be smaller, but have the connections have the same appearance.

how to install a new hard drive

Speaking of size, you’ll also need to make sure you buy a drive with the correct physical dimensions. There are two popular hard drive sizes – 3.5″ and 2.5″. The larger is built for desktop systems, while the smaller is generally for laptops and compact desktops. However, solid state hard drives often come in the 2.5″ size regardless of the type of machine they’re meant to be installed in. This rule isn’t absolute, however, because some all-in-one computers use 2.5″ drives.

Transferring Data From The Old To New Drive

The process of installing a new hard drive is one of the least difficult hardware installation procedures around in terms of the physical effort required. However, the hard drive is one of the most critical components in your system because it stores all of your information. Everything from your operating system to your emails to your favorite songs are stored on your hard drive. Obviously, a straight replacement will leave you without that information.

how to install a hard drive

If you’re using a computer that has more than one hard drive bay you’ll find the process of transferring data from one drive to another to be easy. All you need to do is install the second hard drive in your system and then clone an image of your existing drive using one of the many freeware tools available for this task. Once the old drive’s image has been cloned and placed on the new drive, you can simply remove the old drive or reformat it and use it as a second drive (make sure the clone was successful before taking this step, however!)

how to install a hard drive

Computers that have only a single drive bay are more difficult to work with because you can’t have the new and old drive installed at the same time.You can, however, still clone your old drive to your new one. This is possible by connecting your new drive to your PC with a USB-to-SATA cable or an external hard drive dock. Cloning a drive may take some time because of the bandwidth limitations of USB 2.0, but it will complete eventually.

Replacing The Old Drive

how to install a hard drive

Desktop computer hard drives are usually placed in the lower front half of a mid-tower enclosure and are attached using between two and six screws. The process isn’t overly difficult, but is detailed enough to warrant its own post

Laptops are different, but easier. Most laptops will offer a plastic hard drive bay cover on the bottom of the laptop that is held in with one or two screws. Removing the cover will reveal the drive, which is itself typically attached with a few screws. Installing a replacement drive is simply a matter of taking the existing drive out and putting the new drive in its place. The power and data connections are built into the mount itself, so you don’t have to worry about tracking down the cables. Please note that not all laptops are intended to be user serviceable in this way,  so please read your laptop’s manual for information about hard drive replacement before proceeding.

Booting & Partitioning

how to install a new hard drive

Once you’ve replaced your old drive you will, of course, want to boot up your PC to make sure everything is functioning well. Assuming you did clone your data from your old drive to your new once, this process should be painless. Your PC will barely realize that anything has changed. You should probably visit the Disk Management utility, which can be found by visiting the Administrative Tools –> Computer Management section of the Windows Control Panel, to ensure that Windows is recognizing and using all of your new hard drive’s capacity. If it isn’t, you can extend the current partition to cover the free space or create a new drive partition.

If you didn’t end up cloning your drive, this step will be irrelevant, as you’ll have to format and partition the new drive during the installation process of your operating system.


Hopefully this brief post has given you the information you need to learn how to install a new hard drive. If you have any questions, feel free to post a comment.

Troubleshooting Ricoh Aficio MP2501 SP studio

A very serious and common problem with Ricoh Aficio MP 2501 SP is the System error SC 520-00 . When the registration motor is rotating but does not rotate as it should. The cause of this would be Motor Lock or Defective motor driver.

That could be the case but before you start searching for a new motor or a spare part, you should alwways check some other thinks first.

The first think to do is to make sure that the error is not sympomatic and the error could be erased from the system machine if you reset the machine status from maintanance mode .

So some process to do :

  1. Go to maintanance mode by pressing Clear (yellow) button, 1 0 7, and press and hold Stop (orange) button for 5 seconds. Go down to find sc and reset the main function . then you should restart the machine from the main switch.
  2. Some suggest that you should cheat the machine with the side door open
  3. If nothing happens, then you should start searching what could be blockin the motor from running as it should be. The main motor is being tested every 20 milisecondw to check the proper functionality. If something is blocking it, it generates sc520 error code. So you should check every component that could be blocking it. The first to check would be the Drum Unit or fuser. It could be blocked by something or by excessive toner inside Drum Unit. The Fix is quite easy for technicians. They should open it up and reduce the toner inside the drum unit that is causing the motor to turn slow. That’s it.
  4. Another check could be the defective fuser. You should check for defective rollers or debris inside

That’s it. This can save you a lot of money and make your machine work ready.