remote digital ioopback towards the remote user dte. the ioopback is performed by connecting the local data channel receive signal to the data channel transmit input, as shown in figure 5-2. the test signal is provided by the remote user dte that must receive ils own transmission.

    this test fully checks the user data link, including the cables connecting the remote dte to fcd-2, the remote fcd-2, the transmission plant connecting the two fcd-2s and the local fcd-2.