In this respect, it is similar to a conventional television scanning a single line. The gun was set to a default energy close to Vcr1, and the bits from the computer fed to the gun to modulate the voltage up and down such that 0's would be below Vcr1 and 1's above it. By the time the beam reached the other side of the line, a pattern of short dashes was drawn for each 1, while 0's were empty locations.