The 4T port adapter provides the following electrical interfaces: EIA/TIA-232, EIA/TIA-449, EIA-530. X.21, and V.35. Each interface complies with its specific interface specifications. The cable attached to each 4T port adapter's interface ports determines its type (EIA/TIA-232, and so forth) and its mode (DCE or DTE). The 4T port adapter contains the enabled LED, standard on all port adapters, and a one status LED for each port. After system initialization, the enabled LED goes on to indicate that the 4T port adapter has been enabled for operation.