NCP>LOOP CIRCUIT DMC-0 COUNT 5 LENGTH 20

          This command initiates a circuit-level loopback test over circuit
          DMC-0.  The software loops five messages, 20 bytes in length with
          mixed binary information.

      NCP>LOOP CIRCUIT UNA-0 NODE 224

          This command initiate an Ethernet circuit-level loopback test
          with a node whose address is 224.  In this example, the NODE
          parameter with a node-id of 224 was used in place of the
          PHYSICAL ADDRESS parameter.