Firstly Atari themselves put out several models beyond the 410/1010/XC11/XC12,
generally only known in eastern Europe:
XCA12 Program Recorder -in same case as XC12...Poland
CA12 Program Recorder -in same case as XC12...Poland
XL12 Program Recorder -XC12 w/slight changed design. Czech/Slovak/Poland
XC13 Program Recorder -XC12 which was "T2000 ready". Czech/Slovak/Poland
Unlike other microcomputer systems of the time, it was very unusual to use
anything but Atari-brand program cassette recorders. One third-party product
released was the:
Compu-Mate, by General Electric (GE, G.E.)
Includes external interface module, a power cord/adapter, and SIO cable.
No second SIO port - must be at end of SIO chain.