  We examine the disc--jet connection in stellar mass and supermassive black
holes by investigating the properties of their compact emission in the hard
X-ray and radio bands. We compile a sample of ~100 active galactic nuclei with
measured mass, 5 GHz core emission, and 2-10 keV luminosity, together with 8
galactic black holes with a total of about 50 simultaneous observations in the
radio and X-ray bands. Using this sample, we study the correlations between the
radio (L_R) and the X-ray (L_X) luminosity and the black hole mass (M). We find
that the radio luminosity is correlated with both M and L_X, at a highly
significant level. We show how this result can be used to extend the standard
unification by orientation scheme to encompass unification by mass and
accretion rate.
