In telecommunication, the term clearing has the following meanings:

• A sequence of events used to disconnect a call and return to the ready state.

• Removal of data from an AIS, its storage devices, and other peripheral devices with storage capacity, in such a way that the data may not be reconstructed using normal system capabilities (i.e., through the keyboard).

Note: An AIS need not be disconnected from any external network before clearing takes place. Clearing enables a product to be reused within, but not outside of, a secure facility. It does not produce a declassified product by itself, but may be the first step in the declassification process.

Source: from Federal Standard 1037C and from MIL-STD-188 and from the National Information Systems Security Glossary

• Clearing (financial). All activities from the time a trade is made until it is finally settled (see settlement). Some of the activities in clearing are reporting/ monitoring, risk margining, netting of trades to single positions, tax handling, failure handling, ...