diff --git a/serial-linux.go b/serial-linux.go
index 6926b1e..7da99a2 100644
--- a/serial-linux.go
+++ b/serial-linux.go
@@ -50,7 +50,7 @@ func (s *serialPortStruct) writeLoop() {
 
 func (s *serialPortStruct) readLoop() {
 	s.read = make(chan []byte)
-	b := make([]byte, 80) // Max. frame length according to Hamlib.
+	b := make([]byte, maxSerialFrameLength)
 	for {
 		n, err := s.pty.Master.Read(b)
 		if err != nil {
diff --git a/serialstream.go b/serialstream.go
index 4623c44..ff9bef3 100644
--- a/serialstream.go
+++ b/serialstream.go
@@ -4,6 +4,8 @@ import (
 	"github.com/nonoo/kappanhang/log"
 )
 
+const maxSerialFrameLength = 80 // Max. frame length according to Hamlib.
+
 type serialStream struct {
 	common streamCommon