What is a simbox and how it affects Telecommunication operators

A device able to insert multiple simcards and is used to generate many concurrent mobile calls.

It is legally used by mobile operators to test networks and illegally used for intercepting and diverting international incoming calls and setting a new on-net call, this in order to lower the cost of the call.

Impact of Simbox

1. Call quality is highly affected.
2. Incorrect statistics on international calls – leading to loss in Interconnect Revenue, either higher amounts paid or less gained due to the ‘disguised’ calls that appear as local.

You can read more about simboxes @
https://en.wikipedia.org/wiki/SIM_box
http://www.xintec.com/fraud-management/what-is-simbox-fraud-and-why-is-it-so-hard-to-beat/