Ethereum shutdown
Publish: 2021-05-12 13:51:28
1. The price of bitcoin has gone up abruptly, and the old miners who left the mine have begun to return. Many new people have also poured into the mining instry. However, the price has gone up, and the difficulty of mining bitcoin is also rising. How can we make money from mining now
- - talking about the mining cost of bitcoin -
the first thing to consider is the cost if you want to make money. If the profit is greater than the cost, it is worth doing. We all know how much bitcoin costs, so let's calculate the cost
1. Mining machine cost: the "number" of bitcoin is a problem-solving process, which can't be calculated by human brain alone. Therefore, mining people need to buy mining machines and keep calculating. The more mining machines, the stronger the computing power
2. Electricity charges: mining machines are big consumers of high power. How much electricity does it consume? Let's put it this way. At present, the electricity consumption of bitcoin and Ethereum mining has surpassed Jordan, Iceland, Libya and other small countries, ranking 71st among all countries and regions in the world. You want to cry when electricity is expensive
3. The rent of the place where the mining machine is placed: because the mining machine consumes a lot of electricity, the power supply load of ordinary residential buildings can not be guaranteed at all, so the mining must rent a commercial site separately, and the rent is much more expensive than that of ordinary residential buildings
4. Operation cost: in order to ensure the computing power, the high-power mining machine needs to work 24 hours, which requires someone to maintain it at any time. When the mining machine is in trouble, the cost of hiring someone is required; At the same time, the mining machine is very delicate. If it is too hot or too cold, the vegetables will be stopped. Therefore, the measures of cold air and cold water insulation are needed to help the mining machine run. This is another expense
5. Mining machine update cost: because bitcoin is becoming more and more difficult to dig, the machine that was able to dig a month ago may not be able to dig anything today, and the market will also launch mining machines with greater computing power. The original mining machine is not worth money immediately. If you want to maintain computing power, you need to buy mining machines again
the above bitcoin mining costs all have a marginal effect, that is, the larger the volume is, the lower the corresponding cost will be. Therefore, some super large mines have been built
bitcoin g in the mine will enter the mine pool and be distributed by all participants. Large mines will be built in places where labor and electricity are cheap, such as Venezuela, the legendary miner's paradise, or Iceland, where the climate is favorable and electricity is cheap
as for the cost, everyone will be different. Let's take a look at an average: in 2017, according to the data of elite fixtures, a research institution, Venezuela is the cheapest of 115 mining countries, which is 513 US dollars, while South Korea is the most expensive, which is 26170 us dollars
China's mining cost is US $3172, which is relatively low among 115 countries. However, the cost is an average value. Large mines with low electricity prices must be much lower. If you are a lone ranger, the cost will rise sharply
in a word, if you really want to make money by mining, first of all, unless you are rich enough to build a mine with thousands of machines, you'd better join a mine to dig together. Although you have to share the money, it's still appropriate in the long run because it can greatly rece costs and improve computing power
secondly, whether you dig by yourself or join the mine, you must choose the place with low electricity cost, and the city with abundant hydropower resources is preferred, because hydropower is the cheapest source of power generation in China at present.
- - talking about the mining cost of bitcoin -
the first thing to consider is the cost if you want to make money. If the profit is greater than the cost, it is worth doing. We all know how much bitcoin costs, so let's calculate the cost
1. Mining machine cost: the "number" of bitcoin is a problem-solving process, which can't be calculated by human brain alone. Therefore, mining people need to buy mining machines and keep calculating. The more mining machines, the stronger the computing power
2. Electricity charges: mining machines are big consumers of high power. How much electricity does it consume? Let's put it this way. At present, the electricity consumption of bitcoin and Ethereum mining has surpassed Jordan, Iceland, Libya and other small countries, ranking 71st among all countries and regions in the world. You want to cry when electricity is expensive
3. The rent of the place where the mining machine is placed: because the mining machine consumes a lot of electricity, the power supply load of ordinary residential buildings can not be guaranteed at all, so the mining must rent a commercial site separately, and the rent is much more expensive than that of ordinary residential buildings
4. Operation cost: in order to ensure the computing power, the high-power mining machine needs to work 24 hours, which requires someone to maintain it at any time. When the mining machine is in trouble, the cost of hiring someone is required; At the same time, the mining machine is very delicate. If it is too hot or too cold, the vegetables will be stopped. Therefore, the measures of cold air and cold water insulation are needed to help the mining machine run. This is another expense
5. Mining machine update cost: because bitcoin is becoming more and more difficult to dig, the machine that was able to dig a month ago may not be able to dig anything today, and the market will also launch mining machines with greater computing power. The original mining machine is not worth money immediately. If you want to maintain computing power, you need to buy mining machines again
the above bitcoin mining costs all have a marginal effect, that is, the larger the volume is, the lower the corresponding cost will be. Therefore, some super large mines have been built
bitcoin g in the mine will enter the mine pool and be distributed by all participants. Large mines will be built in places where labor and electricity are cheap, such as Venezuela, the legendary miner's paradise, or Iceland, where the climate is favorable and electricity is cheap
as for the cost, everyone will be different. Let's take a look at an average: in 2017, according to the data of elite fixtures, a research institution, Venezuela is the cheapest of 115 mining countries, which is 513 US dollars, while South Korea is the most expensive, which is 26170 us dollars
China's mining cost is US $3172, which is relatively low among 115 countries. However, the cost is an average value. Large mines with low electricity prices must be much lower. If you are a lone ranger, the cost will rise sharply
in a word, if you really want to make money by mining, first of all, unless you are rich enough to build a mine with thousands of machines, you'd better join a mine to dig together. Although you have to share the money, it's still appropriate in the long run because it can greatly rece costs and improve computing power
secondly, whether you dig by yourself or join the mine, you must choose the place with low electricity cost, and the city with abundant hydropower resources is preferred, because hydropower is the cheapest source of power generation in China at present.
2.
FutureNet (FN FutureNet) is a pyramid marketing company. FutureNet claims to be located in Poland, Europe. It has been established for more than four years and has many operating companies all over the world. The business is spread over more than 190 countries, and about 1000000 paid members claim to make use of the trend of Internet plus big data + virtual currency + doubling. We should make the future coin one of the three largest digital currencies in the future. p> The entry fee of FN future can be divided into six levels: 10 US dollars, 25 US dollars, 50 US dollars, 100 US dollars, 500 US dollars and 1000 US dollars. There can only be three people below each layer, three people on the first layer, nine people on the second layer and 59049 people on the 10th layer. With an investment of 185 US dollars, you can make 800000 US dollars if you reach the 10th layer
FutureNet (FN FutureNet) draws lessons from some routines of Vicat. Under the banner of the decline of the public volleyball team and the victory of the public volleyball team, the MLM organization vigorously carries out head pulling MLM activities. The platform recharge activation adopts bitcoin recharge operation to avoid capital supervision and carry out illegal and criminal activities 
the main characteristics of MLM currency:
1. It is covered with blockchain technology, and the technology is far from the real blockchain principle
2. Not to solve, optimize or change a business pain point in traditional instries
3. The token is not released through the smart contract of Ethereum, and there is no formal trading platform for digital currency, most of which are traded through the platform built by the project party
4
5. There will be rewards after pulling people in
3. It's not reliable.... Yes, there are weekends and so on.. It's just that. After you go in, you will be a salesman.... Every month you have to pull three or four people into the company, or you will face the risk of money dection.
4. I think this question should be very simple. You can refer to it here http://wiki.ubuntu.org.cn/index.php?title=UbuntuHelp : internethowto / zh & variant = zh CN
let's talk about my opinion:
I just installed Ubuntu on disk today. Because of the misunderstanding of partition, I successfully installed it for the third time
then, it took me less than three hours to understand the Internet, updates and so on
I think we must pay attention to the following: when using ubuntn, we must not use the windows way of thinking to think. At most, it is just a little reference
Internet access problem: application (the first menu in the upper left corner) - Accessories - terminal, and then enter sudo pppoeconf
on the open page, and then complete the network card setting according to the prompt
then, every time you need to connect, you can also input pondsl provider on the terminal to access the Internet
these are not difficult. The key is not to get out of the corner
it is suggested to search for relevant questions on the Internet, or read the official Speed Dating Guide. Don't worry, take your time
Ubuntu speed Guide http://wiki.ubuntu.org.cn/index.php?title=Qref/Intrepid &variant=zh-cn
let's talk about my opinion:
I just installed Ubuntu on disk today. Because of the misunderstanding of partition, I successfully installed it for the third time
then, it took me less than three hours to understand the Internet, updates and so on
I think we must pay attention to the following: when using ubuntn, we must not use the windows way of thinking to think. At most, it is just a little reference
Internet access problem: application (the first menu in the upper left corner) - Accessories - terminal, and then enter sudo pppoeconf
on the open page, and then complete the network card setting according to the prompt
then, every time you need to connect, you can also input pondsl provider on the terminal to access the Internet
these are not difficult. The key is not to get out of the corner
it is suggested to search for relevant questions on the Internet, or read the official Speed Dating Guide. Don't worry, take your time
Ubuntu speed Guide http://wiki.ubuntu.org.cn/index.php?title=Qref/Intrepid &variant=zh-cn
5.
EOS can be understood as enterprise operation system, which is a blockchain operating system designed for commercial distributed applications. EOS is a new blockchain architecture, which aims to extend the performance of distributed applications. Note that it is not a currency like bitcoin and Ethereum, but a token based on the EOS software project, known as blockchain 3.0. The main features of EOS are as follows:
1. EOS is a bit similar to Microsoft's windows platform. By creating a developer friendly underlying platform of blockchain, it supports multiple applications running at the same time and provides the underlying template for the development of DAPP
2. EOS solves the problems of delay and data throughput by means of parallel chain and dpos. EOS can process thousands of data per second, while bitcoin has about 7 transactions per second, and Ethereum has 30-40 transactions per second
3. There is no service charge for EOS, and the general audience is more extensive. The network and computing resources needed to develop DAPP on EOS are allocated according to the proportion of EOS owned by developers. When you have EOS, it is equivalent to having computer resources. With the development of DAPP, you can lease your EOS to others. From this point alone, EOS has a wide range of value. To put it simply, if you have an EOS, it is equivalent to having a set of rent to collect rent for others, or having a piece of land to rent for others to build a house< br />
6. Is your phone set? There are some captcha, he was intercepted, and then your mobile phone can't receive it, apple mobile phone, often have this situation
7. Overview of power over Ethernet (POE)
POE (power over Ethernet) refers to the technology that can provide DC power supply for some IP based terminals (such as IP telephone, WLAN access point AP, network camera, etc.) while transmitting data signals without any changes to the existing Ethernet cat. 5 wiring infrastructure. Poe technology can ensure the security of the existing structured cabling, ensure the normal operation of the existing network, and minimize the cost
Poe is also known as power over LAN (POL) or active Ethernet (active Ethernet), sometimes referred to as Ethernet power supply, which is the latest standard specification of using existing standard Ethernet transmission cable to transmit data and power at the same time, and maintains the compatibility with existing Ethernet system and users. IEEE 802.3af standard is a new standard based on POE of power supply system over Ethernet. It adds the relevant standard of direct power supply through network cable on the basis of IEEE 802.3. It is an extension of the existing Ethernet standard and the first international standard on power distribution<
IEEE began to develop this standard in 1999. The earliest participating manufacturers were 3Com, Intel, powerdsine, Nortel, mitel and national semiconctor. However, the shortcomings of the standard have been restricting the expansion of the market. Until June 2003, IEEE approved 802.3af standard, which clearly stipulated the power detection and control matters in remote system, and regulated the power supply mode of router, switch and hub to IP phone, security system and wireless LAN access point through Ethernet cable. The development of IEEE 802.3af includes the efforts of many company experts, which also makes the standard can be tested in all aspects
a typical Ethernet power supply system is shown in Figure 1. The Ethernet switch equipment is reserved in the distribution cabinet, and a midspan hub is used to supply power to the twisted pair of LAN. At the end of the twisted pair, the power supply is used to drive phones, wireless access points, cameras and other devices. To avoid power failure, a UPS can be selected<
Figure 1 a typical Ethernet power supply system
key technology of Poe
system composition and power supply characteristic parameters of Poe
a complete Poe system includes two parts: power souring equipment (PSE) and power device (PD). PSE equipment is the power supply equipment for Ethernet client equipment, and it is also the manager of the whole Poe Ethernet power supply process. PD device is the client device of Poe system, such as IP phone, network security camera, AP, PDA or mobile phone charger and many other Ethernet devices (in fact, any device with power less than 13W can get the corresponding power from RJ45 socket). Based on IEEE 802.3af standard, they establish information contact about PD connection, device type, power consumption level and so on, and supply power to PD through Ethernet according to PSE
the main power supply characteristic parameters of Poe standard power supply system are:
the voltage is between 44 and 57V, and the typical value is 48V
the maximum allowable current is 550mA and the maximum starting current is 500mA
the typical working current is 10 ~ 350mA, and the overload detection current is 350 ~ 500mA
under no-load condition, the maximum required current is 5mA
provide PD equipment with 5 levels of power request (3.84-12.95w), with the maximum power not exceeding 13W
working process of Poe power supply
when the PSE power supply terminal equipment is arranged in a network, the working process of Poe Ethernet power supply is as follows
detection: at the beginning, the PSE device outputs a small voltage at the port until it detects that the cable terminal is connected to a receiving end device supporting IEEE 802.3af standard
PD end equipment classification: when PD is detected at the receiving end, the PSE equipment may classify the PD equipment and evaluate the power loss required by the PD equipment
start power supply: in a configurable time (generally less than 15 minutes) μ s) During the start-up period, PSE equipment began to supply power to PD equipment from low voltage to 48V DC power supply
power supply: provide stable and reliable 48V DC power for PD equipment to meet the power consumption of PD equipment within 15.4W
power off: if the PD device is disconnected from the network, the PSE will quickly (generally within 300-400ms) stop supplying power to the PD device, and repeat the detection process to detect whether the cable terminal is connected to the PD device
when connecting any network device to the PSE, the PSE must first detect whether the device is a PD to ensure that it does not supply current to Ethernet devices that do not meet the POE standard, because this may cause damage. This kind of check is realized by providing a small current limited voltage to the cable to check whether the far end has the required characteristic resistance. Only when the resistance is detected, the full 48V voltage will be provided, but the current is still limited to avoid the terminal equipment in the wrong state. As an extension of the discovery process, PD can also classify the power supply modes that require PSE, which helps PSE to provide power in an efficient way. Once the PSE starts to provide power, it will continuously monitor the PD current input. When the PD current consumption falls below the minimum value, such as when the device is unplugged or when the power consumption of the PD device is overloaded, short circuited or exceeds the power supply load of the PSE, the PSE will disconnect the power supply and start the detection process again
power supply devices can also be provided with a system management capability, such as the application of simple network management protocol (SNMP). This function can provide functions such as night shutdown and remote restart
by studying the power supply mode of Poe, we can see that there are two key issues to be considered in the process of power supply, one is the identification of PD equipment, the other is the capacity of ups in the system
the principle of Poe power supply through cable
there are four pairs of twisted pair in the standard five kinds of network cable, but only two pairs of them are used in l0m Base-T and 100m base-t. IEEE80 2.3af allows two uses, as shown in Figure 2 and figure 3
Figure 2 supplies power through the free pin
Figure 3 supplies power through the data pin
when applying the free pin power supply, the 4 and 5 pins are connected to the positive pole, and the 7 and 8 pins are connected to the negative pole
when the data pin is used for power supply, the DC power supply is added to the midpoint of the transmission transformer, which does not affect the data transmission. In this way, pair 1, 2 and pair 3, 6 can be of any polarity
the standard does not allow the above two cases to be applied at the same time. Power supply equipment PSE can only provide one usage, but power application equipment PD must be able to adapt to both situations. The standard stipulates that the power supply is usually 48V, 13W. It is easy for PD equipment to provide 48V to low voltage conversion, but at the same time, it should have 1500V insulation safety voltage
the POE standard also specifies the unshielded twisted pair cables used to transmit electric power, i.e. Category 3, 5, 5e or 6 cables. It is clear that the existing cable facilities working with them do not need any changes, including category 3, 5, 5e or 6 cables, various short wiring and terminal blocks, power socket leads and connecting hardware, etc. Poe standard is compatible with IEEE 802.3 standard series
two power supply methods of Poe
Poe standard defines two methods for using Ethernet transmission cable to transmit DC power to Poe compatible devices: one is called mid span method, which uses unused free pairs in Ethernet cable to transmit DC power, and the corresponding endpoint PSE supports Ethernet switch, router, router with POE function A hub or other network switching device. Another method is "end span", which is to transmit DC power on the data transmission core at the same time, and the transmission frequency is different from that of Ethernet data signal. The midspan PSE is a dedicated power management device, usually placed with a switch. It has two RJ45 jacks corresponding to each port, one is connected to the switch with a short line, and the other is connected to the remote device. It can be predicted that end span will be popularized rapidly. This is e to the fact that Ethernet data and power transmission adopt common line pair, thus the need to set up independent power transmission special line is eliminated. This is of great significance for the cable with only 8 cores and the matching standard RJ-45 socket
Figure 4 is an example of Poe power supply system, which is composed of power supply equipment PSE, power receiving equipment PD, relevant supporting equipment and Ethernet transmission cable
Fig. 4 example of Ethernet power supply system conforming to IEEE 802.3af Standard
when PD equipment is compatible with POE standard, it can directly supply power from Ethernet cable through RJ-45 socket. For equipment not compatible with POE, DC converter or tap voltage divider can be used to convert its voltage into Poe compatible voltage. These devices, sometimes called active Ethernet splitters, can take the DC voltage from the Ethernet cable and supply it to PD devices through conventional DC sockets
the advantages of Poe technology and expanded application
the advantages of using Ethernet power supply are obvious:
Poe only needs to install and support one cable, which is simple and space-saving, and the equipment can be moved at will
cost saving. Many live equipment, such as video surveillance cameras, need to be installed in places where it is difficult to deploy AC power. Poe makes it no longer need expensive power supply and time-consuming to install power supply, saving cost and time
like data transmission, Poe can monitor and control the device by using simple network management protocol (SNMP)
Poe power supply terminal equipment will only supply power to the equipment that needs power supply. Only when the equipment that needs power supply is connected, the Ethernet cable will have voltage, thus eliminating the risk of leakage on the line
a single UPS can provide power supply for all related equipment in case of power failure
users can automatically and safely mix existing devices and Poe devices on the network, and these devices can coexist with existing Ethernet cables
make network devices easy to manage. Because when the remote device is connected to the network, it can be remotely controlled, reconfigured or reset
in WLAN, Poe can simplify RF test tasks, and access points can be easily moved and accessed
with the establishment of IEEE 802.3af standard, a large number of other applications will emerge rapidly, including bluetooth access point, lighting work, network printer, IP phone, web camera, wireless bridge, building security system, such as access card reader and monitoring system, etc. Users can provide 48V DC power supply on the existing network cable by fusing new power supply devices on the current Ethernet equipment, which reces the total cost of network construction and protects the investment. Some manufacturers have launched procts on the market, such as the midspan hub with power supply
the core of Poe is to transmit 48V rated voltage to PD array through Ethernet cable. IP phone is a kind of receiving equipment. Other devices include Wi Fi device, bluetooth access point, network camera and retail terminal
pots (traditional telephone service) transmits the rated voltage of 48V to the user's phone through the local switch, and this transmission will be carried out as we pick up the phone. But for many specific Poe applications such as VoIP, the key is to know whether NCPI can support these PDS and whether they can be used
POE (power over Ethernet) refers to the technology that can provide DC power supply for some IP based terminals (such as IP telephone, WLAN access point AP, network camera, etc.) while transmitting data signals without any changes to the existing Ethernet cat. 5 wiring infrastructure. Poe technology can ensure the security of the existing structured cabling, ensure the normal operation of the existing network, and minimize the cost
Poe is also known as power over LAN (POL) or active Ethernet (active Ethernet), sometimes referred to as Ethernet power supply, which is the latest standard specification of using existing standard Ethernet transmission cable to transmit data and power at the same time, and maintains the compatibility with existing Ethernet system and users. IEEE 802.3af standard is a new standard based on POE of power supply system over Ethernet. It adds the relevant standard of direct power supply through network cable on the basis of IEEE 802.3. It is an extension of the existing Ethernet standard and the first international standard on power distribution<
IEEE began to develop this standard in 1999. The earliest participating manufacturers were 3Com, Intel, powerdsine, Nortel, mitel and national semiconctor. However, the shortcomings of the standard have been restricting the expansion of the market. Until June 2003, IEEE approved 802.3af standard, which clearly stipulated the power detection and control matters in remote system, and regulated the power supply mode of router, switch and hub to IP phone, security system and wireless LAN access point through Ethernet cable. The development of IEEE 802.3af includes the efforts of many company experts, which also makes the standard can be tested in all aspects
a typical Ethernet power supply system is shown in Figure 1. The Ethernet switch equipment is reserved in the distribution cabinet, and a midspan hub is used to supply power to the twisted pair of LAN. At the end of the twisted pair, the power supply is used to drive phones, wireless access points, cameras and other devices. To avoid power failure, a UPS can be selected<
Figure 1 a typical Ethernet power supply system
key technology of Poe
system composition and power supply characteristic parameters of Poe
a complete Poe system includes two parts: power souring equipment (PSE) and power device (PD). PSE equipment is the power supply equipment for Ethernet client equipment, and it is also the manager of the whole Poe Ethernet power supply process. PD device is the client device of Poe system, such as IP phone, network security camera, AP, PDA or mobile phone charger and many other Ethernet devices (in fact, any device with power less than 13W can get the corresponding power from RJ45 socket). Based on IEEE 802.3af standard, they establish information contact about PD connection, device type, power consumption level and so on, and supply power to PD through Ethernet according to PSE
the main power supply characteristic parameters of Poe standard power supply system are:
the voltage is between 44 and 57V, and the typical value is 48V
the maximum allowable current is 550mA and the maximum starting current is 500mA
the typical working current is 10 ~ 350mA, and the overload detection current is 350 ~ 500mA
under no-load condition, the maximum required current is 5mA
provide PD equipment with 5 levels of power request (3.84-12.95w), with the maximum power not exceeding 13W
working process of Poe power supply
when the PSE power supply terminal equipment is arranged in a network, the working process of Poe Ethernet power supply is as follows
detection: at the beginning, the PSE device outputs a small voltage at the port until it detects that the cable terminal is connected to a receiving end device supporting IEEE 802.3af standard
PD end equipment classification: when PD is detected at the receiving end, the PSE equipment may classify the PD equipment and evaluate the power loss required by the PD equipment
start power supply: in a configurable time (generally less than 15 minutes) μ s) During the start-up period, PSE equipment began to supply power to PD equipment from low voltage to 48V DC power supply
power supply: provide stable and reliable 48V DC power for PD equipment to meet the power consumption of PD equipment within 15.4W
power off: if the PD device is disconnected from the network, the PSE will quickly (generally within 300-400ms) stop supplying power to the PD device, and repeat the detection process to detect whether the cable terminal is connected to the PD device
when connecting any network device to the PSE, the PSE must first detect whether the device is a PD to ensure that it does not supply current to Ethernet devices that do not meet the POE standard, because this may cause damage. This kind of check is realized by providing a small current limited voltage to the cable to check whether the far end has the required characteristic resistance. Only when the resistance is detected, the full 48V voltage will be provided, but the current is still limited to avoid the terminal equipment in the wrong state. As an extension of the discovery process, PD can also classify the power supply modes that require PSE, which helps PSE to provide power in an efficient way. Once the PSE starts to provide power, it will continuously monitor the PD current input. When the PD current consumption falls below the minimum value, such as when the device is unplugged or when the power consumption of the PD device is overloaded, short circuited or exceeds the power supply load of the PSE, the PSE will disconnect the power supply and start the detection process again
power supply devices can also be provided with a system management capability, such as the application of simple network management protocol (SNMP). This function can provide functions such as night shutdown and remote restart
by studying the power supply mode of Poe, we can see that there are two key issues to be considered in the process of power supply, one is the identification of PD equipment, the other is the capacity of ups in the system
the principle of Poe power supply through cable
there are four pairs of twisted pair in the standard five kinds of network cable, but only two pairs of them are used in l0m Base-T and 100m base-t. IEEE80 2.3af allows two uses, as shown in Figure 2 and figure 3
Figure 2 supplies power through the free pin
Figure 3 supplies power through the data pin
when applying the free pin power supply, the 4 and 5 pins are connected to the positive pole, and the 7 and 8 pins are connected to the negative pole
when the data pin is used for power supply, the DC power supply is added to the midpoint of the transmission transformer, which does not affect the data transmission. In this way, pair 1, 2 and pair 3, 6 can be of any polarity
the standard does not allow the above two cases to be applied at the same time. Power supply equipment PSE can only provide one usage, but power application equipment PD must be able to adapt to both situations. The standard stipulates that the power supply is usually 48V, 13W. It is easy for PD equipment to provide 48V to low voltage conversion, but at the same time, it should have 1500V insulation safety voltage
the POE standard also specifies the unshielded twisted pair cables used to transmit electric power, i.e. Category 3, 5, 5e or 6 cables. It is clear that the existing cable facilities working with them do not need any changes, including category 3, 5, 5e or 6 cables, various short wiring and terminal blocks, power socket leads and connecting hardware, etc. Poe standard is compatible with IEEE 802.3 standard series
two power supply methods of Poe
Poe standard defines two methods for using Ethernet transmission cable to transmit DC power to Poe compatible devices: one is called mid span method, which uses unused free pairs in Ethernet cable to transmit DC power, and the corresponding endpoint PSE supports Ethernet switch, router, router with POE function A hub or other network switching device. Another method is "end span", which is to transmit DC power on the data transmission core at the same time, and the transmission frequency is different from that of Ethernet data signal. The midspan PSE is a dedicated power management device, usually placed with a switch. It has two RJ45 jacks corresponding to each port, one is connected to the switch with a short line, and the other is connected to the remote device. It can be predicted that end span will be popularized rapidly. This is e to the fact that Ethernet data and power transmission adopt common line pair, thus the need to set up independent power transmission special line is eliminated. This is of great significance for the cable with only 8 cores and the matching standard RJ-45 socket
Figure 4 is an example of Poe power supply system, which is composed of power supply equipment PSE, power receiving equipment PD, relevant supporting equipment and Ethernet transmission cable
Fig. 4 example of Ethernet power supply system conforming to IEEE 802.3af Standard
when PD equipment is compatible with POE standard, it can directly supply power from Ethernet cable through RJ-45 socket. For equipment not compatible with POE, DC converter or tap voltage divider can be used to convert its voltage into Poe compatible voltage. These devices, sometimes called active Ethernet splitters, can take the DC voltage from the Ethernet cable and supply it to PD devices through conventional DC sockets
the advantages of Poe technology and expanded application
the advantages of using Ethernet power supply are obvious:
Poe only needs to install and support one cable, which is simple and space-saving, and the equipment can be moved at will
cost saving. Many live equipment, such as video surveillance cameras, need to be installed in places where it is difficult to deploy AC power. Poe makes it no longer need expensive power supply and time-consuming to install power supply, saving cost and time
like data transmission, Poe can monitor and control the device by using simple network management protocol (SNMP)
Poe power supply terminal equipment will only supply power to the equipment that needs power supply. Only when the equipment that needs power supply is connected, the Ethernet cable will have voltage, thus eliminating the risk of leakage on the line
a single UPS can provide power supply for all related equipment in case of power failure
users can automatically and safely mix existing devices and Poe devices on the network, and these devices can coexist with existing Ethernet cables
make network devices easy to manage. Because when the remote device is connected to the network, it can be remotely controlled, reconfigured or reset
in WLAN, Poe can simplify RF test tasks, and access points can be easily moved and accessed
with the establishment of IEEE 802.3af standard, a large number of other applications will emerge rapidly, including bluetooth access point, lighting work, network printer, IP phone, web camera, wireless bridge, building security system, such as access card reader and monitoring system, etc. Users can provide 48V DC power supply on the existing network cable by fusing new power supply devices on the current Ethernet equipment, which reces the total cost of network construction and protects the investment. Some manufacturers have launched procts on the market, such as the midspan hub with power supply
the core of Poe is to transmit 48V rated voltage to PD array through Ethernet cable. IP phone is a kind of receiving equipment. Other devices include Wi Fi device, bluetooth access point, network camera and retail terminal
pots (traditional telephone service) transmits the rated voltage of 48V to the user's phone through the local switch, and this transmission will be carried out as we pick up the phone. But for many specific Poe applications such as VoIP, the key is to know whether NCPI can support these PDS and whether they can be used
8. Hello, if rx57000xt digs eth, and the display memory is not enough after power failure, some web pages can not be opened, but other computers can be opened. Shut down and restart it
9. I don't recommend that you delete the data randomly. After you delete the data, your own system can't run.
10. As a past suggestion, you must pay attention to the safety of the principal. There are too many cases of small platforms closing down and running away. Therefore, I suggest you do trading in large exchanges. In China, you can recommend okex, which is the largest exchange in the world. A good platform is the basis for trading bitcoin. Don't go to those unknown Shanzhai platforms.
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