What is the difference between PDA and pad?

Nanjing Science and Technology of the use of industrial PDA and self-made software combined using the method of steel plate management.
So what's the difference between an industrial PDA and the pad we use?
PDA refers to the handheld computer, can help us to complete the mobile work, learning, entertainment and so on. Its range is large.
Classified according to use, divided into industrial-grade PDA and consumer goods PDA. Industrial-grade PDA is mainly used in industrial field, common barcode scanner, RFID Reader, POS machine, etc. can be called PDA, consumer goods PDA includes more, smart phones, tablets, handheld games consoles.

Pad refers to the tablet computer, is a small, portable personal computer, touch screen as the basic input device. Its range is small. Its representative is the ipad, Android tablet.

What is the difference between PDA and pad?