Secure transmission of electronic data via a data communication link is provided between a device and an additional device with independent transmission channels, wherein at least one of the devices is a medical device. Secure transmission comprises the following steps or means: providing a password in the device, receiving the password in the a additional device separate from the data communication link, selecting one of the independent transmission channels, encrypting the channel identification of the selected independent transmission channel using the received password in the additional device, transmitting the encrypted channel identification from the additional device to the device via the data communication link and decrypting the encrypted channel identification in the device, providing a session key in the device and the additional device and transmitting encrypted electronic data between the device and the additional device via the independent transmission channel.