  The ESO Very Large Telescope Interferometer (VLTI) is one of the leading
interferometric facilities. It is equipped with several 8.2 and 1.8m
telescopes, a large number of baselines up to 200m, and with several subsystems
designed to enable high quality measurements and to improve significantly the
limits of sensitivities currently available to long-baseline interferometry.
The full scientific potential of the VLTI can be exploited only if a consistent
set of good quality calibrators is available. For this, a large number of
observations of potential calibrators have been obtained during the
commissioning phase of the VLTI. These data are publicly available. We briefly
describe the interferometer, the VINCI instrument used for the observations,
the data flow from acquisition to processed results, and we present and comment
on the volume of observations gathered and scrutinized. The result is a list of
191 calibrator candidates, for which a total of 12066 observations can be
deemed of satisfactory quality. We present a general statistical analysis of
this sample, using as a starting point the angular diameters previously
available in the literature.We derive the general characteristics of the VLTI
transfer function, and its trend with time in the period 2001 through mid-2004.
A second paper will be devoted to a detailed investigation of a selected
sample, aimed at establishing a VLTI-based homogeneous system of calibrators.
