The MC145421 and MC145425 UDLTs are highspeed data transceivers capable of providing 160 kbps fullduplex data communication over 26 AWG and larger twistedpair cable up to 1 km in length. These devices are primarily used in digital subscriber voice and data telephone systems. In addition, the devices meet and exceed the CCITT recommendations for data transfer rates of ISDNs on a single twisted pair. The devices utilize a 512 kbaud MDPSK burst modulation technique to supply the 160 kbps fullduplex data transfer rates. The 160 kbps rate is provided through four channels. There are two B channels, which are 64 kbps each. In addition, there are two D channels which are 16 kbps each.