STRAHL" is an interactive, stand-alone impurity transport code, which has been used since 1980 on ASDEX and later on JET for the interpretation of spectroscopic measurements. It calculates the impurity ionisation balance on the basis of given plasma parameters and empirical transport models, using atomic physics data sets especially compiled for that purpose. A simple version of neoclassical transport is included but, failing to explain the experimental results, it was only used for occasional testing. Specific line radiation for diagnostic purposes and total radiated power are computed. Rise and decay times for impurity injection can be simulated and particle losses and particle confinement with and without sources are calculated. A change in ionisation balance due to charge­exchange (CX) recombination is implemented in a rudimentary fashion.