diff --git a/framertu.go b/framertu.go
index 75b0e11..0144298 100644
--- a/framertu.go
+++ b/framertu.go
@@ -29,8 +29,8 @@ func NewRTUFrame(packet []byte) (*RTUFrame, error) {
 	}
 
 	frame := &RTUFrame{
-		Address:  uint8(packet[0]),
-		Function: uint8(packet[1]),
+		Address:  packet[0],
+		Function: packet[1],
 		Data:     packet[2 : pLen-2],
 	}
 
@@ -39,8 +39,8 @@ func NewRTUFrame(packet []byte) (*RTUFrame, error) {
 
 // Copy the RTUFrame.
 func (frame *RTUFrame) Copy() Framer {
-	copy := *frame
-	return &copy
+	rtuFrame := *frame
+	return &rtuFrame
 }
 
 // Bytes returns the Modbus byte stream based on the RTUFrame fields
diff --git a/frametcp.go b/frametcp.go
index 7c89d4b..2fd15a3 100644
--- a/frametcp.go
+++ b/frametcp.go
@@ -26,8 +26,8 @@ func NewTCPFrame(packet []byte) (*TCPFrame, error) {
 		TransactionIdentifier: binary.BigEndian.Uint16(packet[0:2]),
 		ProtocolIdentifier:    binary.BigEndian.Uint16(packet[2:4]),
 		Length:                binary.BigEndian.Uint16(packet[4:6]),
-		Device:                uint8(packet[6]),
-		Function:              uint8(packet[7]),
+		Device:                packet[6],
+		Function:              packet[7],
 		Data:                  packet[8:],
 	}
 
@@ -41,8 +41,8 @@ func NewTCPFrame(packet []byte) (*TCPFrame, error) {
 
 // Copy the TCPFrame.
 func (frame *TCPFrame) Copy() Framer {
-	copy := *frame
-	return &copy
+	tcpFrame := *frame
+	return &tcpFrame
 }
 
 // Bytes returns the Modbus byte stream based on the TCPFrame fields
diff --git a/go.mod b/go.mod
new file mode 100644
index 0000000..9f7a954
--- /dev/null
+++ b/go.mod
@@ -0,0 +1,8 @@
+module github.com/zing-dev/mbserver
+
+go 1.15
+
+require (
+	github.com/goburrow/modbus v0.1.0
+	github.com/goburrow/serial v0.1.0
+)
diff --git a/server.go b/server.go
index 0020dd6..33e4320 100644
--- a/server.go
+++ b/server.go
@@ -15,7 +15,7 @@ type Server struct {
 	listeners        []net.Listener
 	ports            []serial.Port
 	requestChan      chan *Request
-	function         [256](func(*Server, Framer) ([]byte, *Exception))
+	function         [256]func(*Server, Framer) ([]byte, *Exception)
 	DiscreteInputs   []byte
 	Coils            []byte
 	HoldingRegisters []uint16
@@ -84,8 +84,10 @@ func (s *Server) handle(request *Request) Framer {
 func (s *Server) handler() {
 	for {
 		request := <-s.requestChan
-		response := s.handle(request)
-		request.conn.Write(response.Bytes())
+		go func() {
+			response := s.handle(request)
+			request.conn.Write(response.Bytes())
+		}()
 	}
 }
 
diff --git a/servertu.go b/servertu.go
index 3f526de..a47939f 100644
--- a/servertu.go
+++ b/servertu.go
@@ -1,6 +1,7 @@
 package mbserver
 
 import (
+	"bytes"
 	"io"
 	"log"
 
@@ -20,30 +21,31 @@ func (s *Server) ListenRTU(serialConfig *serial.Config) (err error) {
 }
 
 func (s *Server) acceptSerialRequests(port serial.Port) {
+	buffer := bytes.Buffer{}
 	for {
-		buffer := make([]byte, 512)
-
-		bytesRead, err := port.Read(buffer)
+		buf := make([]byte, 512)
+		bytesRead, err := port.Read(buf)
+		log.Println("[mbserver] buffer", buf[:bytesRead])
 		if err != nil {
 			if err != io.EOF {
 				log.Printf("serial read error %v\n", err)
 			}
 			return
 		}
-
-		if bytesRead != 0 {
-
-			// Set the length of the packet to the number of read bytes.
-			packet := buffer[:bytesRead]
-
-			frame, err := NewRTUFrame(packet)
+		buffer.Write(buf[:bytesRead])
+		for buffer.Len() > 5 {
+			b := make([]byte, buffer.Len())
+			_, err := buffer.Read(b)
+			if err != nil {
+				log.Printf("buffer read error %v\n", err)
+				break
+			}
+			frame, err := NewRTUFrame(b)
 			if err != nil {
 				log.Printf("bad serial frame error %v\n", err)
 				return
 			}
-
 			request := &Request{port, frame}
-
 			s.requestChan <- request
 		}
 	}