Salbu, in the early 1960's, built, and evaluated on the amateur radio bands, a unique range of both "tuned" and "broad-band" SSB, Solid State, Transceivers.

The "tuned" prototype was further developed and manufactured by SMD in Pinetown and later by RACAL-SMD in Pretoria - large numbers of the RT422B SSB Transceivers were soon in use throughout Africa.