diff --git a/config.h b/config.h
index 0c5c64f..8c8c7e1 100644
--- a/config.h
+++ b/config.h
@@ -110,6 +110,4 @@ void store_setting(int parameter, double value);
 #define STEPPING_MASK (STEP_MASK | DIRECTION_MASK) // All stepping-related bits (step/direction)
 #define LIMIT_MASK ((1<<X_LIMIT_BIT)|(1<<Y_LIMIT_BIT)|(1<<Z_LIMIT_BIT)) // All limit bits
 
-#define INCHES_PER_MM (1.0/25.4) // A conversion rate
-
 #endif
diff --git a/gcode.c b/gcode.c
index b178231..73edefe 100644
--- a/gcode.c
+++ b/gcode.c
@@ -32,6 +32,8 @@
 #include "errno.h"
 #include "serial_protocol.h"
 
+#define MM_PER_INCH (25.4)
+
 #define NEXT_ACTION_DEFAULT 0
 #define NEXT_ACTION_DWELL 1
 #define NEXT_ACTION_GO_HOME 2
@@ -96,7 +98,7 @@ void gc_init() {
 }
 
 inline float to_millimeters(double value) {
-  return(gc.inches_mode ? (value * INCHES_PER_MM) : value);
+  return(gc.inches_mode ? (value * MM_PER_INCH) : value);
 }
 
 // Find the angle in radians of deviance from the positive y axis. negative angles to the left of y-axis, 
diff --git a/serial_protocol.h b/serial_protocol.h
index 16bb448..c7abdc7 100644
--- a/serial_protocol.h
+++ b/serial_protocol.h
@@ -20,13 +20,9 @@
 #ifndef serial_h
 #define serial_h
 
-// A string to let the client know we are ready for a new command
-#define PROMPT "\r\n>>>"
-// A character to acknowledge that the execution has started
-#define EXECUTION_MARKER '~'
-
 // Initialize the serial protocol
 void sp_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();