It's wonderful and lets you accept card in lots of areas around your building and is named a Portable and it has a connectivity with the base cradle which then connects through either internet or your phone.
Most of the time it is diners, cafeteria's or bars that use the latter kind of machine because they must let people use cards when eating at tables but it can be for different uses.
A terminal which is mostly for folk who must take cards on the go and is called the mobile one. It only needs a connection from a sim and network for you to use it. It is one that can be taken outside allowing you to receive cards throughout the United Kingdom and you don't require a landline connection.
The latter is the static machine which is for people that need to take cards in a defined place near to power socket and a phone or Ethernet point.