diff --git a/go.mod b/go.mod
new file mode 100644
index 0000000..2939c13
--- /dev/null
+++ b/go.mod
@@ -0,0 +1,8 @@
+module mbserver
+
+go 1.15
+
+require (
+	github.com/goburrow/modbus v0.1.0
+	github.com/goburrow/serial v0.1.0
+)
diff --git a/go.sum b/go.sum
new file mode 100644
index 0000000..e702ea7
--- /dev/null
+++ b/go.sum
@@ -0,0 +1,4 @@
+github.com/goburrow/modbus v0.1.0 h1:DejRZY73nEM6+bt5JSP6IsFolJ9dVcqxsYbpLbeW/ro=
+github.com/goburrow/modbus v0.1.0/go.mod h1:Kx552D5rLIS8E7TyUwQ/UdHEqvX5T8tyiGBTlzMcZBg=
+github.com/goburrow/serial v0.1.0 h1:v2T1SQa/dlUqQiYIT8+Cu7YolfqAi3K96UmhwYyuSrA=
+github.com/goburrow/serial v0.1.0/go.mod h1:sAiqG0nRVswsm1C97xsttiYCzSLBmUZ/VSlVLZJ8haA=
diff --git a/servertu.go b/servertu.go
index e9c9183..8757c1d 100644
--- a/servertu.go
+++ b/servertu.go
@@ -27,8 +27,8 @@ func (s *Server) acceptSerialRequests(port serial.Port, slaveID uint8) {
 		bytesRead, err := port.Read(buffer)
 		if err != nil {
 			if err != io.EOF {
-				if s.errorHandler != nil {
-					(*s.errorHandler)(fmt.Errorf("[mbserver] serial read error %v", err))
+				if s.onErrorhandler != nil {
+					(*s.onErrorhandler)(fmt.Errorf("[mbserver] serial read error %v", err))
 				}
 			}
 			return
@@ -41,8 +41,8 @@ func (s *Server) acceptSerialRequests(port serial.Port, slaveID uint8) {
 
 			frame, err := NewRTUFrame(packet)
 			if err != nil {
-				if s.errorHandler != nil {
-					(*s.errorHandler)(fmt.Errorf("[mbserver] serial read error %v", err))
+				if s.onErrorhandler != nil {
+					(*s.onErrorhandler)(fmt.Errorf("[mbserver] serial read error %v", err))
 				}
 				return
 			}
@@ -50,8 +50,8 @@ func (s *Server) acceptSerialRequests(port serial.Port, slaveID uint8) {
 				request := &Request{port, frame}
 				s.requestChan <- request
 			} else {
-				if s.errorHandler != nil {
-					(*s.errorHandler)(fmt.Errorf("[mbserver] serial read error %v", err))
+				if s.onErrorhandler != nil {
+					(*s.onErrorhandler)(fmt.Errorf("[mbserver] serial read error %v", err))
 				}
 			}
 
diff --git a/servetcp.go b/servetcp.go
index 6e6f953..7ffa5d7 100644
--- a/servetcp.go
+++ b/servetcp.go
@@ -24,8 +24,8 @@ func (s *Server) accept(listen net.Listener) error {
 				bytesRead, err := conn.Read(packet)
 				if err != nil {
 					if err != io.EOF {
-						if s.errorHandler != nil {
-							(*s.errorHandler)(fmt.Errorf("[mbserver] read error %v", err))
+						if s.onErrorhandler != nil {
+							(*s.onErrorhandler)(fmt.Errorf("[mbserver] read error %v", err))
 						}
 					}
 					return
@@ -35,8 +35,8 @@ func (s *Server) accept(listen net.Listener) error {
 
 				frame, err := NewTCPFrame(packet)
 				if err != nil {
-					if s.errorHandler != nil {
-						(*s.errorHandler)(fmt.Errorf("[mbserver] bad packet error %v", err))
+					if s.onErrorhandler != nil {
+						(*s.onErrorhandler)(fmt.Errorf("[mbserver] bad packet error %v", err))
 					}
 					return
 				}