diff --git a/utils/SerPortServer.c b/utils/SerPortServer.c
index 748a86b..3495163 100755
--- a/utils/SerPortServer.c
+++ b/utils/SerPortServer.c
@@ -1158,7 +1158,9 @@ static int  RS__MAX_ASYNCH =	20;	/* Asynch "ports" 0 - 19 will be allowed */
 	Cl_info[i].remaining -= bytes_got;
 	Cl_info[i].nxt_rply_ptr1 += bytes_got;
 
-	memcpy (Ts_info[indx].tp_ahd, &rcve[bytes_got], (j - bytes_got));
+	if( (j - bytes_got) > 0){
+	  memcpy (Ts_info[indx].tp_ahd, &rcve[bytes_got], (j - bytes_got));
+	}
 	Ts_info[indx].tp_nxt = j - bytes_got;
       }
       if (term_fnd) {		    /* Response complete? */