The PA-4T provides four channel-independent, synchronous serial ports that support full-duplex operation at T1 (1.544 Mbps) and E1 (2.048 Mbps) speeds. Each port supports any of the available interface types: Electronics Industries Association/Telecommunications Industries Association (EIA/TIA)-232, EIA/TIA-449, V.35, X.21, and EIA-530. The cable attached to each PA-4T interface port determines its type (EIA/TIA-232, and so forth) and its mode (DCE or DTE).