ABSTRACT
This chapter reviews the existing techniques in data acquisition and telemetry applied to volcanic monitoring and briefly describes a limited number of representative systems. The instruments used in volcano monitoring must satisfy a number of requirements which distinguish them from electronic equipment used in the laboratory. When defining a system to provide information from sensors placed on a volcano, a choice has to be made between several basic options. The most important criterion is whether the system will be digital or analogue, if digital, it is important to decide at which point the analogue-to-digital conversion will be made, thus determining which parts of the systems will be analogue and which digital. Numerous radio or telephone links, and digital acquisition and transmission systems are currently being used to monitor active volcanoes. The choice of data storage depends on the data type and the storage duration required.
