25 years ago, a friend of mine (yes, I had friends once) purchased a TEC-1 kit and kindly dumped the ROM for me. It lived on cassette, then over to floppy, and finally to the hard drive of my (still working) 386.
For the one or two Australians who remember the TEC-1, it has finally been emulated in MESS.
You won't find any software on the net, because the TEC-1 has no storage or communication facilities. Just a 20-key pad, 6 LED digits and a speaker. The ROM does have 3 built-in "games", and a welcome messgae from the programmer. These can be called up with the proper key sequences.