The model with the two cassette drives is the 733 ASR (Automatic Send/Receive) and the model without is the 733 KSR (Keyboard Send/Receive) Is this really a 733? It does not look like one. According to the picture in my "Operating Instructions", the KSR looks identical to the ASR, except for the cassette driver, and it is not designed to be portable. But perhaps it's a 733 in a Tymshare carrying case. Does yours look virtually identical to the one on the picture? /Lars