guard PER references
diff --git a/skeletons/T61String.c b/skeletons/T61String.c
index 115d7d4..411ad87 100644
--- a/skeletons/T61String.c
+++ b/skeletons/T61String.c
@@ -22,8 +22,13 @@
 	OCTET_STRING_encode_der,
 	OCTET_STRING_decode_xer_hex,
 	OCTET_STRING_encode_xer,
+#ifdef	ASN_DISABLE_PER_SUPPORT
+	0,
+	0,
+#else
 	OCTET_STRING_decode_uper,
 	OCTET_STRING_encode_uper,
+#endif	/* ASN_DISABLE_PER_SUPPORT */
 	0, /* Use generic outmost tag fetcher */
 	asn_DEF_T61String_tags,
 	sizeof(asn_DEF_T61String_tags)