The TRS-80 Model III

The TRS 80 was built round the Z80 processor at a clock speed of 2.03 MHz  and has a 14k ROM with 16k of RAM expandable to 48k. The built in display is monochrome and capable of displaying text on 16 lines with either 32 or 64 characters, the interface's included tape and RS232.

The unit was capable of holding up to two 5.25" floppy disk units.

I bought this one for £3  while on holliday several years ago and lugged it home on the train (300 mile) but it was worth it.