A collection of "SIM boxes" that hold from hundreds to more than a thousand SIM cards, and each SIM contains a cellular phone number. SIM farms are 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. SIM farms can also be used for remote monitoring as well as testing functions in a new cellular network. Illegitimate calls from SIM farms are made for scamming the public. See
SIM card.