tm990 301 00The TM 990/301 Microterminal was introduced in 1978 as a small console for the TMS9900 based computer system TMtm990 301 01 990/100M. This Microterminal is obviously based on a normal TI-30, the most successful scientific calculator of that time frame. 
Dismantling the TM 990/301 Microterminal discovers a completely different internal construction. Instead the small printed circuit board (PCB) of the TI-30 and all the other calculators using its housing we notice a big PCB based on a TMS1000 single-chiptm990 301 02 microcomputer. Remember that the TMS1000 is still recognized as the first true microcomputer and found its way into millions of products. A similar approach using a standard calculator housing for industrial products could be found with the TI-510 PLC Programmer.