diff --git a/pdu/submit.go b/pdu/submit.go
index a2aa012..a205cfd 100644
--- a/pdu/submit.go
+++ b/pdu/submit.go
@@ -57,3 +57,14 @@ type (
 	SUBMIT_MULTI      struct{}
 	SUBMIT_MULTI_RESP struct{}
 )
+
+func (p *SUBMIT_SM) Encode() []byte {
+	return []byte{}
+}
+func (p *SUBMIT_SM) EncodeInto(buf *[]byte) {
+}
+func (p *SUBMIT_SM) Decode(data []byte) {
+}
+func (p *SUBMIT_SM) Size() uint32 {
+	return 0
+}