The VFU receives instructions from the printer and from the computer. For example, when the VFU receives an FF code
from the TOP OF FORM button on the control panel, it looks for an FF code hole on the tape and stops the paper linefeed
when it finds one. When the VFU receives an FF command from the computer, it advances to the next FF hole and
ignores any VT hole. When it receives a VT command from the computer, it advances to the next FF or VT hole.
To prepare a VFU tape, it is necessary to follow table 2-2, and perform the following steps:
a. Form Length. Measure, the form length (distance between fold-line perforations) in inches. Determine, from
the run book or programmer's instructions, the number of lines per inch (lpi).
b. Number of Line Spaces Available. Multiply the form length by the number of lines per inch. For example, a
form length of 6 inch X 6 1pi = 36 line spaces available.
c. Tape Length per Form Length. Knowing the number of lines on the form, look at table 2-2 and find the tape
length per form length. If the tape length per form length is less than six inches, it will be too small to properly fit the VFU.
d. Total Tape Length. Find the total tape length required. Count the sprocket holes. For example, there are 10
sprocket holes per inch. A tape length of 7.2 in. contains 72 sprocket holes.
e. Number of Repetitive VTFF Formats. If tape length per form length is less than six inches, more than one
VTFF format is required. For each repetition of the VTFF (format, an FF hole is required in line one. The run book or
programmer's instructions will state where and how many VT holes are required. The VT holes must be repeated for each
repetition of the VTFF format.
f. Example. You have a 6 inch form at 6 1pi with tabs on lines 10, 20, and 30. A 6 inch form at 6 1pi has 36 line
spaces. Table 2-2 says tape length per form length is 3.6 inch total tape length is 7.2 inch (72 sprocket holes), and 2
VTFF repetitions are needed. Line 1 and 37 on the tape will need FF holes, and lines 10, 20, 30 46, 56, and 66 will need