The ADTRAN DDM+ HDSL4 Transceiver U

The ADTRAN DDM+ HDSL4 Transceiver Unit for the Central Office (H4TU-C) (ADTRAN P/N 1223403L1) is the Central Office (CO) unit used to deploy an HDSL4 T1 circuit using 4-wire metallic facilities. The unit occupies one slot in a DDM+ shelf. The DS1 or DSX-1 input signal is supplied from the network. The HDSL4 signals are provided to the local loop. The ADTRAN DDM+ H4TU-C works in conjunction with the ADTRAN H4TU-R and up to two H4Rs to provide a DS1 service on the local loop.