Ethernet: two in one. How to build multifunctional networks


Company Premium-Line Systems is the manufacturer of solutions for cable infrastructure Cat. 5e, 6, 6A, 7, 8, as well as optical networks, is fully prepared to meet the new IEEE 802.3bt standard, presenting products on the market that satisfy the requirements of this document.

In everyday life, Internet connections are often made using PoE (Power over Ethernet) technology. Initially, it was intended for IP-telephony, as well as Wi-Fi access points, to which there was no ability to connect the power cable. The standard data cable consists of four symmetrical (twisted) pairs, but the 100BASE-TX protocol then used only two of them. The remaining free pairs could be used to supply power to the equipment. This feature has been implemented in special network switches. Later, with the advent of new standards, they began to use all four pairs for the electricity transmission, fully implementing the principle of “Ethernet: two in one.”

Some historical facts

Thanks to Cisco, PoE technology became an international standard in June 2003, after being ratified by the IEEE Institute as the 802.3af standard. In the field of IP-telephony, this made the system as convenient as a traditional telephone network, where the devices are powered from the telephone station. In 2009, the IEEE 802.3at standard was created, which allowed providing power equal to 30 W at the output from the PoE source using two pairs of 5e cat cable.

The new IEEE 802.3bt standard already provides two options: type 3 (60 W) and type 4 (100 W). This means that it is possible to transmit about 100 watts of electrical power through a single cable to power devices, such as wireless access points, thermal cameras with PTZ functions, LED lights, large displays, etc. This is made possible by using all four pair cable. Table 1 presents the current existing PoE standards.

Options for the POEMinimum power, WNum. of pairsMaximum current per pair, mA
PoE Type 115,42350
PoE Plus (Type 2)30,02600
4-pair PoE1 (Type 3)60,04600
4-pair PoE1 (Type 4)90,04960
Power over HDBase-T (POH)100,04960

Working temperature range

When implementing cable infrastructure, it is necessary to take into account that the use of PoE can cause an increase in temperature in cable bundles. This will degrade the signal-to-noise ratio and lead to degradation of the insulation materials.

According to ISO / IEC, the standard operating temperature for structured cabling is –20 to 60 ° C. In this case, the maximum permissible length of a constant line is indicated for a temperature of 20 ° C.

T, °C202530354045505560
The length of the constant line, m908885838078757370


Nevertheless, when designing a cabling system, you can always find ways to reduce the temperature in bundles by spacing them apart, reducing the number of cables in each of them, using products with less resistance (larger conductor cross-section) and larger diameter. We recommend using category 6A cables and above, such as the Premium-Line Category 6A S / FTP installation cable, LSOH, Gray, 600 MHz or the Premium-Line Category 7 / 6A S 1000 FTP Installation Cable, LSOH, 1000 MHz.

About Testing

In practice, sometimes there is a need for direct connection of equipment using the connector – without using an outlet and patch cord.

The ANSI – TIA568.2 – D standard introduces a new Modular Plug Termination Link (MPTL) connection model. For such solution a 25-year warranty is provided. Direct-connected line test can be performed with a Fluke DSX – 5000 cable analyzer using two adapters: a permanent connection at one end and a patch cord at the other. Test values are tested for compliance with TIA Permanent Link restrictions.

Today, there are no disputes concerning the convenience and necessity of PoE. In an era of rapid development of smart buildings and the “Internet of things”, this technology has already taken its strong position in the market. Premium-Line is ready to build a new generation of information networks right now, offering clients the appropriate systems, quality and service.

Vladyslav Ritskyi, Technical Director

Premium-Line Systems GmbH