Radio Shack Model 4P
TRS-80 Model 4P
The Model 4 also had the ability to display 640×240 or 512×192 high-resolution monochrome graphics with an optional board. A "luggable" version known as the Model 4P (1983) was a self-contained unit with a case design similar to that of a portable sewing machine.
Early versions of the Model 4 mainboard were designed to accept a Zilog Z8000 16 bit CPU upgrade board to replace the Z80 8 bit CPU but this option was never released.