Mouse inventor Douglas C. Engelbart passed away last Tuesday at the age of 88. During his lifetime, Engelbart has made many pioneering contributions to the computer and internet industries, including videoconferencing, hyperlinks, text editing, and other technologies we use daily. On December 19th, 1968, Engelbart demonstrated a box-shaped device to about 1,000 technicians at Brooks Hall in San Francisco. Two scrollable wheels formed the "XY coordinates of the display system." This is considered to be a mouse. The first public display, at the time, was a concept that was unheard of.
Afterwards, Engelbart conducted picture and voice communications with a colleague 30 miles away, which was considered the first video conference. He also explained the theory of how to associate information pages with text-based links. This is the embryonic form of the Internet architecture. Decades later, the show was called the "mother of all kinds of demonstrations" in the technology industry.
In that era, computers were mainly tools used by government researchers and technology enthusiasts, and Engelbart did not receive huge wealth because of its invention. The Stanford Research Institute applied for a mouse patent and licensed it to Apple for US$40,000.
In 2000, Engelbart was awarded the American National Technology and Innovation Medal by US President Bill Clinton, affirming that he “created the foundation of personal computing, including continuous real-time interaction based on cathode ray tube displays and mice, hypertext links, text editing, and networks. Journals, screen television conferences, remote collaborative work."
Optical Line Terminal (OLT)
POE (Power Over Ethernet) refers to the use of IP-based terminals (such as IP phones, wireless LAN access points AP, network cameras) without any changes to the existing Ethernet Cat.5 cabling infrastructure. Etc.) The technology that can provide DC power for such devices while transmitting data signals is a switch that supports Power over Ethernet.
POE is also known as a power supply system based on local area network (POL, Power over LAN) or Active Ethernet (Active Ethernet), sometimes also referred to as Power over Ethernet for short. This is the use of existing standard Ethernet transmission cables to transmit data and data at the same time. The latest standard specification of electric power, and maintains compatibility with existing Ethernet systems and users. The IEEE 802.3af standard is a new standard based on the POE of the Ethernet power supply system. It adds related standards for direct power supply through the network cable on the basis of IEEE 802.3. It is an extension of the existing Ethernet standard and the first international standard for power distribution. standard.
IEEE began to develop the standard in 1999, and the earliest participating vendors were 3Com, Intel, PowerDsine, Nortel, Mitel and National Semiconductor. However, the shortcomings of this standard have been restricting the expansion of the market. Until June 2003, the IEEE approved the 802.3af standard, which clearly stipulates the power detection and control items in the remote system, and connects routers, switches, and hubs to IP phones, security systems, and wireless LANs through Ethernet cables. The method of power supply for points and other equipment is regulated. The development of IEEE 802.3af includes the efforts of many company experts, which also allows the standard to be tested in all aspects.
The IEEE 802.3at standard was formulated in 2005 and promulgated in 2009. The 802.3at standard output power can reach 30W, and the available power at the receiving end is 25.5W.
The IEEE 802.3 working group and various manufacturer alliances launched POH-POWER OVER HDBASET in the industry at the end of 2012.
Using the current 4-Pair four-pair wire technology plus, the bilateral power supply can reach 60-100W power, which can be achieved by using 5 or 6 types of wires. It is used in high-definition video promotion to supply power to 42" LED TVs. According to the new regulations in 2010, the power consumption of 42" LED TVs needs to be less than 70W.
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