Telemetering is a process that is used to receive data from technical instruments. This technique also sometimes called remote metering, while the information gathered is referred as telemetry. Data collected through telemetering can be sent via physical cables, radio signals, or other remote transmission methods.
The word telemetering comes from the Greek term for "remote measure." Remote metering was first developed in the mid 1800s. In 1845, information from the Tsar of Russia's palace was monitored by the Russian Army. French scientists in Paris monitored weather sensors located on Mont Blanc in 1874. Both of these early examples of telemetering used physical wires to transmit information from one location to another.
It was not until 1930 that remote metering using wireless methods became practical. Both French and Russian scientists developed wireless telemetry projects in that year, and used Morse code to send weather measurements to monitoring stations. Wireless telemetry became a vital part of missile and rocket launches in the middle of the 20th century. Experts in Russia and the United States used remote metering to track guidance and atmospheric measurements during the space race between these two countries.
Several methods of telemetering are available. Signals can be sent over long distances using radio waves. Similarly, infrared signals can also be used. Infrared telemetry requires a direct line of sight to be available between the receiver and the transmitting location. Despite this disadvantage, infrared remote metering signals are less prone to interference than radio telemetry.
Telemetry signals do not always move directly from the monitored location to a receiver. Sometimes, remote metering uses a network of repeaters to increase the range of the signal. The wireless cellular network in the United States is one example of this method. Data gathered from one side of the country, for instance, can be sent hundreds or thousands of miles as a text message over the same network that is used to make phone calls. Using existing infrastructure such as cellular or satellite networks greatly increases the range and simplicity of modern telemetering processes.
Sending data is a vital part of many activities, and is not limited to scientific or military use. Monitoring the speed of a race car and tracking the location of ambulances are two common examples of remote metering. Even such common conveniences as vending machines and automatic teller machines often send telemetry containing updates on how much currency or stock they hold.