diff --git a/doc/structure.txt b/doc/structure.txt
index 93cb1bd..21c5757 100644
--- a/doc/structure.txt
+++ b/doc/structure.txt
@@ -3,10 +3,10 @@ The general structure of Grbl
 
 The main processing stack:
 
-'serial_protocol' : Accepts command lines from the serial port and passes them to 'gcode' for execution.
+'protocol' : Accepts command lines from the serial port and passes them to 'gcode' for execution.
                     Provides status responses for each command.
                   
-'gcode'           : Recieves gcode from 'serial_protocol', parses it according to the current state
+'gcode'           : Recieves gcode from 'protocol', parses it according to the current state
                     of the parser and issues commands via '..._control' modules
                   
 'spindle_control' : Commands for controlling the spindle.
diff --git a/main.c b/main.c
index ac9c54d..5179c6b 100644
--- a/main.c
+++ b/main.c
@@ -37,7 +37,7 @@
 
 int main(void)
 {
-  sp_init();        
+  protocol_init();        
   settings_init();  
   plan_init();      
   st_init();        
@@ -46,7 +46,7 @@ int main(void)
                     
   for(;;){
     sleep_mode(); // Wait for it ...
-    sp_process(); // ... process the serial protocol
+    protocol_process(); // ... process the serial protocol
   }
   return 0;   /* never reached */
 }
diff --git a/protocol.c b/protocol.c
index 488836b..bdd5cfc 100644
--- a/protocol.c
+++ b/protocol.c
@@ -51,14 +51,14 @@ void status_message(int status_code) {
   }
 }
 
-void sp_init() 
+void protocol_init() 
 {
   beginSerial(BAUD_RATE);  
   printPgmString(PSTR("\r\nGrbl " GRBL_VERSION));
   printPgmString(PSTR("\r\n"));  
 }
 
-void sp_process()
+void protocol_process()
 {
   char c;
   while((c = serialRead()) != -1) 
diff --git a/protocol.h b/protocol.h
index 597205e..318adcf 100644
--- a/protocol.h
+++ b/protocol.h
@@ -21,10 +21,10 @@
 #define serial_h
 
 // Initialize the serial protocol
-void sp_init();
+void protocol_init();
 
 // Read command lines from the serial port and execute them as they
 // come in. Blocks until the serial buffer is emptied. 
-void sp_process();
+void protocol_process();
 
 #endif