diff --git a/src/components/real/cdh/c2a_communication.hpp b/src/components/real/cdh/c2a_communication.hpp
index ea7afef13..c749d90e3 100644
--- a/src/components/real/cdh/c2a_communication.hpp
+++ b/src/components/real/cdh/c2a_communication.hpp
@@ -6,8 +6,6 @@
 #ifndef C2A_COMMUNICATION_H_
 #define C2A_COMMUNICATION_H_
 
-namespace s2e::components {
-
 // If the character encoding of C2A is UTF-8, the following functions are not necessary,
 // and users can directory use SendFromObc_C2A and ReceivedByObc_C2A UART
 // TODO: Delete these functions since C2A is changed to use UTF-8
@@ -25,6 +23,4 @@ int OBC_C2A_I2cReadRegister(int port_id, const unsigned char i2c_address, unsign
 int OBC_C2A_GpioWrite(int port_id, const bool is_high);
 bool OBC_C2A_GpioRead(int port_id);  // return false when the port_id is not used
 
-}  // namespace s2e::components
-
 #endif  // C2A_COMMUNICATION_H_
diff --git a/src/components/real/cdh/on_board_computer_with_c2a.cpp b/src/components/real/cdh/on_board_computer_with_c2a.cpp
index 639e87f5e..407c39369 100644
--- a/src/components/real/cdh/on_board_computer_with_c2a.cpp
+++ b/src/components/real/cdh/on_board_computer_with_c2a.cpp
@@ -133,15 +133,6 @@ int ObcWithC2a::ReceivedByObc_C2A(int port_id, unsigned char* buffer, int offset
   return port->ReadRx(buffer, offset, length);
 }
 
-// If the character encoding of C2A is UTF-8, these functions are not necessary,
-// and users can directory use SendFromObc_C2A and ReceivedByObc_C2A
-int OBC_C2A_SendFromObc(int port_id, unsigned char* buffer, int offset, int length) {
-  return ObcWithC2a::SendFromObc_C2A(port_id, buffer, offset, length);
-}
-int OBC_C2A_ReceivedByObc(int port_id, unsigned char* buffer, int offset, int length) {
-  return ObcWithC2a::ReceivedByObc_C2A(port_id, buffer, offset, length);
-}
-
 int ObcWithC2a::I2cConnectPort(int port_id, const unsigned char i2c_address) {
   if (i2c_com_ports_c2a_[port_id] != nullptr) {
     // Port already used
@@ -212,16 +203,6 @@ int ObcWithC2a::I2cComponentReadCommand(int port_id, const unsigned char i2c_add
   return 0;
 }
 
-int OBC_C2A_I2cWriteCommand(int port_id, const unsigned char i2c_address, const unsigned char* data, const unsigned char length) {
-  return ObcWithC2a::I2cWriteCommand(port_id, i2c_address, data, length);
-}
-int OBC_C2A_I2cWriteRegister(int port_id, const unsigned char i2c_address, const unsigned char* data, const unsigned char length) {
-  return ObcWithC2a::I2cWriteRegister(port_id, i2c_address, data, length);
-}
-int OBC_C2A_I2cReadRegister(int port_id, const unsigned char i2c_address, unsigned char* data, const unsigned char length) {
-  return ObcWithC2a::I2cReadRegister(port_id, i2c_address, data, length);
-}
-
 int ObcWithC2a::GpioConnectPort(int port_id) {
   if (gpio_ports_c2a_[port_id] != nullptr) {
     // Port already used
@@ -255,8 +236,28 @@ bool ObcWithC2a::GpioRead_C2A(int port_id) {
   return port->DigitalRead();
 }
 
-int OBC_C2A_GpioWrite(int port_id, const bool is_high) { return ObcWithC2a::GpioWrite_C2A(port_id, is_high); }
+}  // namespace s2e::components
 
-bool OBC_C2A_GpioRead(int port_id) { return ObcWithC2a::GpioRead_C2A(port_id); }
+// C2A用
+// If the character encoding of C2A is UTF-8, these functions are not necessary,
+// and users can directory use SendFromObc_C2A and ReceivedByObc_C2A
+int OBC_C2A_SendFromObc(int port_id, unsigned char* buffer, int offset, int length) {
+  return s2e::components::ObcWithC2a::SendFromObc_C2A(port_id, buffer, offset, length);
+}
+int OBC_C2A_ReceivedByObc(int port_id, unsigned char* buffer, int offset, int length) {
+  return s2e::components::ObcWithC2a::ReceivedByObc_C2A(port_id, buffer, offset, length);
+}
 
-}  // namespace s2e::components
+int OBC_C2A_I2cWriteCommand(int port_id, const unsigned char i2c_address, const unsigned char* data, const unsigned char length) {
+  return s2e::components::ObcWithC2a::I2cWriteCommand(port_id, i2c_address, data, length);
+}
+int OBC_C2A_I2cWriteRegister(int port_id, const unsigned char i2c_address, const unsigned char* data, const unsigned char length) {
+  return s2e::components::ObcWithC2a::I2cWriteRegister(port_id, i2c_address, data, length);
+}
+int OBC_C2A_I2cReadRegister(int port_id, const unsigned char i2c_address, unsigned char* data, const unsigned char length) {
+  return s2e::components::ObcWithC2a::I2cReadRegister(port_id, i2c_address, data, length);
+}
+
+int OBC_C2A_GpioWrite(int port_id, const bool is_high) { return s2e::components::ObcWithC2a::GpioWrite_C2A(port_id, is_high); }
+
+bool OBC_C2A_GpioRead(int port_id) { return s2e::components::ObcWithC2a::GpioRead_C2A(port_id); }