Voltage converter with folding housing

The device has a housing (12) at least partly enclosing a mains plug (3,4), an equipment plug (8) for connection to a communications terminal and a voltage conversion circuit. The housing has a second part (6) that slides relative to a first part (2) and forms a holder (9) for a terminal. The device can be changed between transport and charging positions. In the transport position the housing parts can be moved relative to each other to occupy less space than in the charging position.