Abstract: A source facsimile apparatus includes a modem having a variable transmission rate and is connected by a radio link to a destination facsimile apparatus which is located in a mobile subscriber station within a radio network. Facsimile data is transmitted at a selected data transmission rate from the source facsimile apparatus to a modem within an interworking function located in the radio network. A buffer memory stores the facsimile data received by the modem of the interworking function. The facsimile data is then transmitted from the buffer memory via the radio link to the destination facsimile apparatus within the mobile station. If the radio link does not allow facsimile data to be sent to the mobile station at about the same rate it is being received by the modem of the interworking function, the latter is changed to bring the two into closer conformity.