With the Amstrad PPC-512 and 640, Amstrad wanted to make the cheapest portable PC compatible computer, in the same way as the Amstrad PC1512 was for desktop computers.
But, despite its pleasant form, this computer suffered due to its poor 9" LCD screen. It had one or two 3.5" 720 KB floppy drives and some versions could also be found with a 10 or 20 MB internal hard disk.
If you were tired of the poor LCD screen, you could connect a monochrome or CGA monitor to the PPC at home. The Amstrad CPC series monitors could be used too.
The differences between the PPC-512 and PPC-640 were a different colour case, a built-in modem (v21, v22, v22 bis and v23 protocols) and 640 KB RAM for the PPC-640. Both versions could run with 10 C size batteries (1 hour battery life), or with an external AC adaptor.