Wireless keyboard and mouse technology classification and detailed explanation
The world's first mouse with 27 MHz RF wireless technology was released by Logitech in 1991, and the industry giant released the first wireless keyboard and mouse kit in 1998. This was the beginning of the market for keyboards and mice using 27 MHz RF wireless technology.
27 MHz RF refers to a technology that uses the 27 MHz ISM (Industrial, Scientific, Medical) wireless frequency band, with an output power of <54 dBuV/m. There are four worldwide channels in this frequency band: two for wireless keyboards and two for wireless mice; because the longest effective transmission distance of 27 MHz is only 6 feet (182.88 cm), in order to prevent frequency interference and In order to prevent frequency interference and poor transmission, some of the newer wireless keyboard and mouse products use the dual-channel program. For example, the dual-channel wireless keyboard uses both 27.095Mhz (channel 1) and 27.195Mhz (channel 2) frequency bands, while the early single-channel wireless keyboard uses only 27.095Mhz or 27.195Mhz frequency bands; similarly, the mouse, dual-channel wireless mouse uses both 27.045Mhz (channel 1) and 27.145Mhz (channel 2) frequencies. channel 1) and 27.145Mhz (channel 2) scheme, while the single-channel wireless mouse only uses the frequency of 27.045Mhz or 27.145Mhz. In this case, wireless keyboard and mouse is not only not easy to interfere with each other, but also because of the use of dual-channel signal and not easy to appear signal "crash" situation.
Logitech V400 mouse, using 27Mhz wireless technology
In addition, because other wireless network devices rarely use the 27Mhz frequency, so this type of keyboard and mouse products from other wireless devices and the possibility of interference is not very large. Although occupying the advantages of mature technology, low cost and low risk of interference, the disadvantages of the 27Mhz band are also relatively obvious. First, this type of keyboard and mouse products only support one-way transmission, that is, only support the mouse transmitter to the signal receiver to send a signal and can not "retrograde". In addition, 27MHz technology because of the transmission rate, must work continuously, so power consumption is also relatively large. In addition, the wireless security level is lower, the effective transmission distance is shorter, etc. are 27Mhz frequency keyboard and mouse products inevitable disadvantages.