Block transfer attempt

In telecommunication, a block transfer attempt is a coordinated sequence of user and telecommunication system activities undertaken to effect transfer of an individual block from a source user[?] to a destination user.

Note: A block transfer[?] attempt begins when the first bit of the block crosses the functional interface between the source user and the telecommunication system. A block transfer attempt ends either in successful block transfer or in block transfer failure[?].

Source: from Federal Standard 1037C