Abstract: A method, apparatus, computer program product and arrangement for testing radio network data connections. The method comprises establishing, by means of radio network terminals, simultaneous data connections in accordance with the TCP/IP (Transmission Control Protocol/Internet Protocol) protocol or the UDP/IP (User Datagram Protocol/Internet Protocol) protocol from the host computer to at least one server connected to the radio network. This is performed by establishing beach data connection from the host computer to a different public IP (Internet Protocol) address of the server, and dynamically establishing a dedicated unambiguous route for each data connection, whereby the data connections to different IP addresses travel along different routes via different terminals and their air interfaces. Each established data connection may be measured separately.

Abstract: The invention relates to a high-pressure fan which comprises an electric motor provided with a shaft that goes through it; blade wheels which are mainly made of a carbon fibre-based composite material, arranged on both sides of the electric motor and mounted directly on the shaft of the electric motor; fan housings surrounding the blade wheels; and an intermediate channel which connects a pressure opening of one fan housing to a suction opening of the other fan housing, the intermediate channel being integrated into the base structure of the high-pressure fan.

Abstract: The invention relates to a high-pressure fan which comprises an electric motor (1) provided with a shaft (2) that goes through it; blade wheels (3, 4) which are mainly made of a carbon fibre-based composite material, arranged on both sides of the electric motor (1) and mounted directly on the shaft (2) of the electric motor; fan housings (5, 6) surrounding the blade wheels (3, 4); and an intermediate channel (7) which connects a pressure opening (9) of one fan housing (5) to a suction opening (11) of the other fan housing (6), the intermediate channel (7) being integrated into the base structure (8) of the high-pressure fan.