Echelle spectra of HD 183143 [B7Iae, E(B-V)=1.27] were obtained on three nights, at a resolving power R=38000 and with a signal-to-noise ratio ~1000 at 6400{AA} in the final, combined spectrum. A catalog is presented of 414 diffuse interstellar bands (DIBs) measured between 3900 and 8100{AA} in this spectrum. The central wavelengths, the widths (FWHM), and the equivalent widths of nearly all of the bands are tabulated, along with the minimum uncertainties in the latter. Among the 414 bands, 135 (or 33%) were not reported in four previous, modern surveys of the DIBs in the spectra of various stars, including HD 183143. The principal result of this study is that the great majority of the bands in the catalog are very weak and fairly narrow. Typical equivalent widths amount to a few m{AA}, and the bandwidths (FWHM) are most often near 0.7{AA}.