Table 1
                           DB-25 pin assignments

                 Pin Name Signal       Pin Name Signal
                 -----------------------------------------
                  1  FG   Frame ground 14  STD  Secondary
                                                TD

                  2  TD   Transmitted  15  TC   Transmit
                          data                  clock

                  3  RD   Received     16  SRD  Secondary
                          data                  RD

                  4  RTS  Request to   17  RC   Receive
                          send                  clock

                  5  CTS  Clear to     18  -    Unassigned
                          send

                  6  DSR  Data set     19  SRTS Secondary
                          ready                 RTS
                                                Data
                  7  SG   Signal       20  DTR  terminal
                          ground
                                                ready
                                                Signal
                  8  DCD  Data carrier 21  SQ   quality
                          signal
                                                detector

                  9  -    Positive     22  RI   Ring
                          voltage               indicator

                 10  -    Negative     23  DRS  Data rate
                          voltage               selector
                                                Clock
                 11  -    Unassigned   24  SCTE transmit
                                                external

                 12  SDCD Secondary    25  BUSY Busy
                          DCD

                 13  SCTS Secondary
                          CTS