--- a/src/drv_tapi_cid.c
+++ b/src/drv_tapi_cid.c
@@ -1424,6 +1424,8 @@ static IFX_int32_t cid_lookup_transparen
 
          cidfsk_set_tx_time (pTxData, &pConfData->TapiCidFskConf);
 
+         fallthrough;
+
       case IFX_TAPI_CID_GEN_TYPE_DTMF:
          memcpy (pTxData->cidBuf[IFX_TAPI_CID_GEN_TYPE_DTMF].pBuf,
             pMessage[0].transparent.data, pMessage[0].transparent.len);
@@ -1497,6 +1499,7 @@ static IFX_int32_t cid_prepare_data(TAPI
          break;
       case IFX_TAPI_CID_STD_KPN_DTMF:
          /*lint -fallthrough*/
+         fallthrough;
       case IFX_TAPI_CID_STD_KPN_DTMF_FSK:
          if (IFX_TAPI_CID_HM_ONHOOK == pTxData->txHookMode)
          {
@@ -1506,6 +1509,7 @@ static IFX_int32_t cid_prepare_data(TAPI
          }
          /* KPN CID Type 2 (off-hook) always using FSK */
          /*lint -fallthrough*/
+         fallthrough;
       default:
          pTxData->cidGenType = IFX_TAPI_CID_GEN_TYPE_FSK;
          break;
@@ -1532,6 +1536,7 @@ static IFX_int32_t cid_prepare_data(TAPI
                break;
 
             /*lint -fallthrough*/
+            fallthrough;
          case IFX_TAPI_CID_GEN_TYPE_FSK:
 
             if (IFX_TAPI_CID_STD_NTT == pConfData->nStandard)
@@ -2036,6 +2041,7 @@ static FSM_STATUS_t cid_fsm_alert_exec(T
          }
          pTxData->nCidSubState++;
          /*lint -fallthrough*/
+         fallthrough;
       case 1:
          if (pConfData->OSIoffhook && pConfData->nSAStone)
          {
@@ -2052,6 +2058,7 @@ static FSM_STATUS_t cid_fsm_alert_exec(T
          }
          pTxData->nCidSubState++;
          /*lint -fallthrough*/
+         fallthrough;
       case 2:
          if (pConfData->nSAStone)
          {
@@ -2069,6 +2076,7 @@ static FSM_STATUS_t cid_fsm_alert_exec(T
          }
          pTxData->nCidSubState++;
          /*lint -fallthrough*/
+         fallthrough;
       default:
          /* Play CAS tone on data channel, use unprotected function, protection
             is done around cid_fsm_alert_exec */
@@ -3458,6 +3466,7 @@ IFX_int32_t TAPI_Phone_CID_Stop_Tx(TAPI_
          }
          /* deliberately fall through */
          /*lint -fallthrough*/
+         fallthrough;
       case TAPI_CID_STATE_ACK:
          /* deactivate the DTMF override - last two params are ignored */
          if (ptr_chk(pDrvCtx->SIG.DTMFD_Override, ""))
@@ -3469,6 +3478,7 @@ IFX_int32_t TAPI_Phone_CID_Stop_Tx(TAPI_
          }
          /* deliberately fall through */
          /*lint -fallthrough*/
+         fallthrough;
       case TAPI_CID_STATE_SENDING:
          TAPI_Stop_Timer (pTxData->CidTimerID);
          break;
@@ -4066,6 +4076,7 @@ IFX_int32_t TAPI_Phone_Get_CidRxData (TA
       /* If the fifo is not empty take the data from the fifo first. */
       /* deliberately fallthrough to default case */
       /*lint -fallthrough*/
+      fallthrough;
    default:
       /* Allow readout of data in all other states not handled above.
          When there is no data in the fifo TAPI_statusErr is returned. */
--- a/src/drv_tapi_dial.c
+++ b/src/drv_tapi_dial.c
@@ -319,6 +319,8 @@ static IFX_void_t ifx_tapi_dial_OnTimer(
          /* NOTE: the "break" statement has been intentionally omitted */
          /*lint -fallthrough */
 
+         fallthrough;
+
       case TAPI_HOOK_STATE_DIAL_L_VAL:
          /* digit_l_min expires: onhook has lasted long enough to be a
             certain low pulse (not noise). The next state is the overlap with
--- a/src/drv_tapi_event.c
+++ b/src/drv_tapi_event.c
@@ -1545,6 +1545,7 @@ IFX_int32_t IFX_TAPI_Event_Dispatch_Proc
                   /**\todo put in device fifo */
                   pEvent->ch = IFX_TAPI_DEVICE_CH_NUMBER;
                   /*lint -fallthrough */
+                  fallthrough;
                case  IFX_TAPI_ERRSRC_LL_CH:
                   pEvent->data.value |= IFX_TAPI_ERRSRC_LL;
                   break;
--- a/src/drv_tapi_ioctl.c
+++ b/src/drv_tapi_ioctl.c
@@ -1552,6 +1552,7 @@ static IFX_int32_t  TAPI_IoctlCh (IFX_TA
       /* Dial Services */
          ret = TAPI_statusNotSupported;
          /*lint -fallthrough*/
+         fallthrough;
       default:
          bHandled = IFX_FALSE;
          break;