Superconductor-insulator-normal metal (SIN) and superconductor-insulator-superconductor (SIS) tunnel junctions provide important information on pairing state symmetry and mechanism. Measurements of such junctions on high {Tc} superconductors (HTS) are reported using mechanical point contacts, which generally display the optimum characteristics that can be obtained from HTS native-surface tunnel barriers. New tunneling data on the infinite-layer cuprate, Sr{sub 1-x}Nd(subscript x)CuO2 are reported which show a remarkable similarity to another electron-doped cuprate, Nd{sub 1.85}Ce{sub 0.85}CuO4. In particular, there is a strong, asymmetric linear background conductance that is indicative of inelastic tunneling from a continuum of states. A discussion is given of the anomalous dip feature found in the tunneling and photoemission data on BSCCO 2212. It is shown that a similar feature is found in many cuprate junctions and that this dip scales with the gap energy over a wide range. New data on the single-layer, tetragonal cuprate, Tl2Ba2CuO6 (Tl2201) are presented and discussed in light of recent published results on the similar compound HgBa2CuO4 (Hg1201). The HG1201 data display a low, flat sub-gap tunneling conductance which is consistent with a BCS density of states whereas the T12201 data display a cusp-like feature at zero bias which is more consistent with d(subscript x)2-{sub y}2 symmetry.