Telemetry is a technology which allows the remote measurement and reporting of information of interest to the system designer or operator. The word is derived from Greek roots tele = remote, and metron = measure.

Telemetry typically refers to wireless communications (i.e. using a radiofrequency system to implement the data link) but can also refer to data transfer over other media, such as a telephone or computer network or via an optical link.

Systems which need instructions and data sent to them in order to operate require the counterpart of telemetry, telecommand.

It is an enabling technology for large complex systems such as spacecraft boosters , oil rigs and chemical plants because it allows automatic monitoring, alerting, and record-keeping necessary for safe, efficient operations.

Telemetry also is used for patients who are at risk of abnormal heart activity. Such patients are outfitted with measuring, recording and transmitting devices. A data log can be useful in diagnosis of the patient's condition by doctors. An alerting function can summon nurses if the patient is suffering from an acute or dangerous condition.

Space agencies such as NASA, ESA, and other agencies use telemetry/telecommand systems to operate spacecraft and satellites.

As in other telecommunications fields, international standards exist for telemetry equipment and software. ESA's CCSDS being one such standard.

In wildlife study and management, telemetry is used to follow members of endangered species. Such animals are now commonly equipped with instrumentation ranging from simple tags to cameras, GPS packages and transceivers to provide position and other information to the scientists, producers, activists, regulators, or other human agencies.

See also

• remote sensing
• instrumentation
• reconnaissance satellites, tapping of communications routing or switching centers (e.g. Echelon)
• automatic data processing.
• M2M