1 files changed, 4 insertions, 0 deletions
diff --git a/ztcfg.c b/ztcfg.c
index b746767..583c4ce 100755
--- a/ztcfg.c
+++ b/ztcfg.c
@@ -730,6 +730,10 @@ int main(int argc, char *argv[])
 						}
 						if (cc[x].sigtype && ioctl(fd, ZT_CHANCONFIG, &cc[x])) {
 							fprintf(stderr, "ZT_CHANCONFIG failed on channel %d: %s (%d)\n", x, strerror(errno), errno);
+							if (errno == EINVAL) {
+								fprintf(stderr, "Did you forget that FXS interfaces are configured with FXO signalling\n"
+									"and that FXO interfaces use FXS signalling?\n");
+							}
 							close(fd);
 							exit(1);
 						}