The invention relates to a
data transmission method and equipment in a telecommunication
system, particularly in a situation where the maximum
data rate of a
traffic channel is equal to one user
data rate at a terminal interface. A
mobile station inserts terminal interface status information in redundant parts of redundant user data elements of an end-to-end
transmission protocol and sends them through the
traffic channel without that the status information raises the
data rate. If no user data elements are received at the terminal interface, auxiliary frames, in which the terminal interface status information can be transmitted, are generated. A mobile services switching centre separates the terminal interface status information from the redundant data elements or auxiliary frames at the receiving end.