diff --git a/tools/sigcheck.c b/tools/sigcheck.c
new file mode 100644
index 0000000..642bab8
--- /dev/null
+++ b/tools/sigcheck.c
@@ -0,0 +1,82 @@
+/* tools/sigcheck.c — per-port SDI signal scanner, run on host with SDK installed */
+#include <stdio.h>
+#include <unistd.h>
+#include <time.h>
+#include "videomaster/VideoMasterHD_Core.h"
+#include "videomaster/VideoMasterHD_Sdi.h"
+
+static ULONG rx_types[8] = {
+    VHD_ST_RX0,VHD_ST_RX1,VHD_ST_RX2,VHD_ST_RX3,
+    VHD_ST_RX4,VHD_ST_RX5,VHD_ST_RX6,VHD_ST_RX7
+};
+
+int main(void) {
+    ULONG dll, nb;
+    if (VHD_GetApiInfo(&dll,&nb)!=VHDERR_NOERROR||nb==0) { fprintf(stderr,"no boards\n"); return 1; }
+    HANDLE board;
+    if (VHD_OpenBoardHandle(0,&board,NULL,0)!=VHDERR_NOERROR) { fprintf(stderr,"board open fail\n"); return 1; }
+
+    printf("Port | Result\n");
+    printf("-----|-------\n");
+
+    for (int p = 0; p < 8; p++) {
+        HANDLE stream = NULL;
+        ULONG r = VHD_OpenStreamHandle(board, rx_types[p],
+                                       VHD_SDI_STPROC_DISJOINED_VIDEO,
+                                       NULL, &stream, NULL);
+        if (r != VHDERR_NOERROR) {
+            printf("  %d  | OPEN_FAIL rc=%lu\n", p, r);
+            fflush(stdout);
+            continue;
+        }
+        VHD_SetStreamProperty(stream, VHD_CORE_SP_TRANSFER_SCHEME, VHD_TRANSFER_SLAVED);
+        VHD_SetStreamProperty(stream, VHD_CORE_SP_BUFFERQUEUE_DEPTH, 4);
+        if (VHD_StartStream(stream) != VHDERR_NOERROR) {
+            VHD_CloseStreamHandle(stream);
+            printf("  %d  | START_FAIL\n", p);
+            fflush(stdout);
+            continue;
+        }
+
+        ULONG std = (ULONG)NB_VHD_VIDEOSTANDARDS;
+        ULONG clk = VHD_CLOCKDIV_1;
+        struct timespec deadline, now;
+        clock_gettime(CLOCK_MONOTONIC, &deadline);
+        deadline.tv_sec += 4;
+        while (1) {
+            clock_gettime(CLOCK_MONOTONIC, &now);
+            if (now.tv_sec>deadline.tv_sec || (now.tv_sec==deadline.tv_sec && now.tv_nsec>=deadline.tv_nsec)) break;
+            VHD_GetStreamProperty(stream, VHD_SDI_SP_VIDEO_STANDARD, &std);
+            if (std != (ULONG)NB_VHD_VIDEOSTANDARDS) break;
+            struct timespec ts = {0, 100000000L};
+            nanosleep(&ts, NULL);
+        }
+        VHD_GetStreamProperty(stream, VHD_SDI_SP_CLOCK_DIVISOR, &clk);
+        VHD_StopStream(stream);
+        VHD_CloseStreamHandle(stream);
+
+        if (std == (ULONG)NB_VHD_VIDEOSTANDARDS) {
+            printf("  %d  | NO SIGNAL\n", p);
+        } else {
+            int ntsc = (clk == VHD_CLOCKDIV_1001);
+            int w=1920,h=1080,fn=30,fd=1;
+            switch(std) {
+                case VHD_VIDEOSTD_S274M_1080p_60Hz: fn=ntsc?60000:60;fd=ntsc?1001:1; break;
+                case VHD_VIDEOSTD_S274M_1080p_50Hz: fn=50;fd=1; break;
+                case VHD_VIDEOSTD_S274M_1080p_30Hz: fn=ntsc?30000:30;fd=ntsc?1001:1; break;
+                case VHD_VIDEOSTD_S274M_1080p_25Hz: fn=25;fd=1; break;
+                case VHD_VIDEOSTD_S274M_1080p_24Hz: fn=ntsc?24000:24;fd=ntsc?1001:1; break;
+                case VHD_VIDEOSTD_S274M_1080i_60Hz: fn=ntsc?30000:30;fd=ntsc?1001:1; break;
+                case VHD_VIDEOSTD_S274M_1080i_50Hz: fn=25;fd=1; break;
+                case VHD_VIDEOSTD_S296M_720p_60Hz: w=1280;h=720;fn=ntsc?60000:60;fd=ntsc?1001:1; break;
+                case VHD_VIDEOSTD_S296M_720p_50Hz: w=1280;h=720;fn=50;fd=1; break;
+                default: break;
+            }
+            printf("  %d  | SIGNAL  std=%lu  %dx%d  %d/%d\n", p, std, w, h, fn, fd);
+        }
+        fflush(stdout);
+        usleep(200000);
+    }
+    VHD_CloseBoardHandle(board);
+    return 0;
+}