A collection of "SIM boxes," each of which holds from hundreds to more than a thousand SIM cards. The SIM farm is used for both legitimate and illegitimate purposes. Each SIM provides a voice channel to a recipient, which enables a large number of phone calls to be made in a short period.
Legitimate calls may be a promotion of some type to the general public or an internal message to a huge workforce. They can be used for remote monitoring as well as testing functions in a new cellular network. Illegitimate calls are made for scamming the public. See
SIM card.