The paper deals with a test campaign performed on a regenerative repeater with an onboard baseband switching matrix (BBSM), able to set up a satellite-switched, time-division multiple-access (SS-TDMA) system. We first address the optimisation of the transmission channel (filters, TWTA back-off etc. ) on the basis of BER measurements, and then examine some functional tests including a TDMA terminal as a traffic terminal simulator.