The formatter selects the desired bit streams from the samplers, adds timing and other information, fans the bit streams in or out (combines several slow input signals onto one tape track or spreads one fast input signal over several tape tracks), establishes the barrel roll scheme used to rotate the bit stream/track mapping with time, and sends the output signals to the tape recorders. As many as 32 bit streams can be formatted, with a bitstream:track multiplexing scheme of 4:1, 2:1, 1:1, 1:2, or 1:4, which allows for very flexible input signal to output tape track switching. VLBA and Mark III data formats are supported. Up to 16 pulse cal tones or state counts can be detected simultaneously. Up to 4 Mbits can be captured and sent to the site computer and on to the AOC for various tests, including real time fringe checks.