F3 - KFT-1 and KFT-2 INTERFACE                                                                                                                                      Pin connections refer to those at the KFT-x end of the wiring loom.                                                                                         E>  PIN     SIGNAL       DESCRIPTION                                          <E    ========================================================================        PL1.1   MUTE CTRL    Active-high output used to mute radio audio                PL1.2   LED          Active-low output used to control LED driver               PL1.3   MIC MUTE     Active-high output used to mute microphone                 PL1.4   TX ON        Active-low output used to enable the transmitter           PL1.5   QUIET/OPEN   Active-low input from the QUIET/OPEN switch logic          PL1.6   TXCALL       Active-low input from the TXCALL switch logic              PL1.7   BUSY IN      Active-high input from the channel-busy logic              PL1.8   VIN          Positive power supply connection                           PL1.9   PTT IN       Active-low input from the PTT switch logic                 PL1.10  GND          Negative power supply connection, ground return            PL1.11  VDATA        Active-high serial data input for variable digit(s)        PL1.12  VCLOCK       Positive-edge clock input for variable digit(s)                                                                                            PL2.1   /GRP DEC     Active-low input from extnl Group decoder (KFT-1)          PL2.2   SIG IN       Audio signal input                                         PL2.3   TONE OUT     Encode tone output, high impedance when not encoding       PL2.4   ALERT        Audible alert tone output, low when not active.                                                                                                                                                                        