1 9-pin d connector

   

    2 pin signals

    1: received line signal detector (rlsd)

    2: received data (rd)

    3: transmitted data (td)

    4: dte ready (drt cd)

    5: signal ground (sgnd)

    6: dce ready (dcr cc)

    7: request to send (rts)

    8: clear to send (cts)

    9: ring indicator (ri)