B unit
DLU handles analog and ISDN lines and includes codecs for analog lines, one of the "BORSCHT" functions for subscriber lines. Digital signals are assigned a time slot. DLU concentrates traffic onto an LTG-B unit, as well as Primary Rate ISDN and V5.2 connections. Supervision and address signalling (dial pulse, DTMF) are also integrated in the DLU. For PCM30 (E-1) connections to other exchanges, LTG-C Units are used, which also handle signalling including SS7, MFC R2 signalling, IKZ (dial pulse), and E&amp;M.