diff --git a/logging.c b/logging.c
index 865fe9b8..c3634274 100644
--- a/logging.c
+++ b/logging.c
@@ -351,7 +351,7 @@ void log_packet(void *handle, int direction, int type,
 	    }
 	    dumpdata[10+2+3*(p%16)] = smalldata[0];
 	    dumpdata[10+2+3*(p%16)+1] = smalldata[1];
-	    dumpdata[10+1+3*16+2+(p%16)] = (isprint(c) ? c : '.');
+	    dumpdata[10+1+3*16+2+(p%16)] = (c >= 0x20 && c < 0x7F ? c : '.');
 	    output_pos = (p%16) + 1;
 	}