diff --git a/device/utils.go b/device/utils.go
new file mode 100644
index 0000000..bf5bfaa
--- /dev/null
+++ b/device/utils.go
@@ -0,0 +1,54 @@
+/*
+ * Copyright 2018-present Open Networking Foundation
+
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+
+ * http://www.apache.org/licenses/LICENSE-2.0
+
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package device
+
+import (
+	"fmt"
+
+	"gerrit.opencord.org/voltha-bbsim/common/logger"
+	log "github.com/sirupsen/logrus"
+	"strconv"
+)
+
+func OnuToSn(onu *Onu) string {
+	// FIXME
+	// see https://github.com/opencord/voltha/blob/master/voltha/adapters/openolt/openolt_device.py#L929-L943
+	return string(onu.SerialNumber.VendorId) + "00000" + fmt.Sprint(onu.IntfID) + "0" + fmt.Sprintf("%x", onu.OnuID-1)
+}
+
+func LoggerWithOnu(onu *Onu) *log.Entry {
+
+	if onu == nil {
+		logger.Warn("utils.LoggerWithOnu has been called without Onu")
+		return logger.GetLogger()
+	}
+
+	return logger.GetLogger().WithFields(log.Fields{
+		"serial_number": OnuToSn(onu),
+		"interfaceId":   onu.IntfID,
+		"onuId":         onu.OnuID,
+		"oltId":         onu.OltID,
+	})
+}
+
+func ConvB2S(b []byte) string {
+	s := ""
+	for _, i := range b {
+		s = s + strconv.FormatInt(int64(i/16), 16) + strconv.FormatInt(int64(i%16), 16)
+	}
+	return s
+}