In Europe, typically the E1 Primary Rate Interface is provided by telecommunication service providers. It has a gross data transmission rate of 2.048 megabits per second and is divided into 32 channels with 64 kilobit per second each. Out of these 32 channels, 30 channels are so-called B-channels, which are available as bearer channels. The data transmission rate of all bearer channels together comes to 1920 kilobit per second. The two remaining channels are divided into a 64 kilobit per second signalling channel (D-channel) and a 64 kilobit per second synchronisation channel.