low mobile (Lm)

In the digital mobile radio systems GSM and DCS, the channels have been designated with the letters "B" and "D" in analogy to ISDN and a small "m" has been added for mobile to distinguish them: Bm and Dm. For services that cannot use the Dm channel, an additional traffic channel with a low data rate was created, the "low-rate traffic channel", or Lm for short, which stands for low mobile.