Cisco offers a variety of connectivity, expansion and upgrade modules and cards to accommodate the customer specific needs. Cisco's components are easily and inexpensively upgradeable as customer requirements change.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: EIA/TIA-232, EIA/TIA-449, V.35, X.21, EIA-530.