diff --git a/Marlin/src/HAL/DUE/HAL.h b/Marlin/src/HAL/DUE/HAL.h
index 9d00d9d11dfb..54a977c2d8f3 100644
--- a/Marlin/src/HAL/DUE/HAL.h
+++ b/Marlin/src/HAL/DUE/HAL.h
@@ -35,67 +35,9 @@
 
 #include <stdint.h>
 
-#include "../../core/serial_hook.h"
-
-// ------------------------
-// Serial ports
-// ------------------------
-
-typedef ForwardSerial1Class< decltype(Serial) > DefaultSerial1;
-typedef ForwardSerial1Class< decltype(Serial1) > DefaultSerial2;
-typedef ForwardSerial1Class< decltype(Serial2) > DefaultSerial3;
-typedef ForwardSerial1Class< decltype(Serial3) > DefaultSerial4;
-extern DefaultSerial1 MSerial0;
-extern DefaultSerial2 MSerial1;
-extern DefaultSerial3 MSerial2;
-extern DefaultSerial4 MSerial3;
-
-#define _MSERIAL(X) MSerial##X
-#define MSERIAL(X) _MSERIAL(X)
-
-#if SERIAL_PORT == -1 || ENABLED(EMERGENCY_PARSER)
-  #define MYSERIAL1 customizedSerial1
-#elif WITHIN(SERIAL_PORT, 0, 3)
-  #define MYSERIAL1 MSERIAL(SERIAL_PORT)
-#else
-  #error "The required SERIAL_PORT must be from 0 to 3, or -1 for USB Serial."
-#endif
-
-#ifdef SERIAL_PORT_2
-  #if SERIAL_PORT_2 == -1 || ENABLED(EMERGENCY_PARSER)
-    #define MYSERIAL2 customizedSerial2
-  #elif WITHIN(SERIAL_PORT_2, 0, 3)
-    #define MYSERIAL2 MSERIAL(SERIAL_PORT_2)
-  #else
-    #error "SERIAL_PORT_2 must be from 0 to 3, or -1 for USB Serial."
-  #endif
-#endif
-
-#ifdef SERIAL_PORT_3
-  #if SERIAL_PORT_3 == -1 || ENABLED(EMERGENCY_PARSER)
-    #define MYSERIAL3 customizedSerial3
-  #elif WITHIN(SERIAL_PORT_3, 0, 3)
-    #define MYSERIAL3 MSERIAL(SERIAL_PORT_3)
-  #else
-    #error "SERIAL_PORT_3 must be from 0 to 3, or -1 for USB Serial."
-  #endif
-#endif
-
-#ifdef MMU_SERIAL_PORT
-  #if WITHIN(MMU_SERIAL_PORT, 0, 3)
-    #define MMU_SERIAL MSERIAL(MMU_SERIAL_PORT)
-  #else
-    #error "MMU_SERIAL_PORT must be from 0 to 3."
-  #endif
-#endif
-
-#ifdef LCD_SERIAL_PORT
-  #if WITHIN(LCD_SERIAL_PORT, 0, 3)
-    #define LCD_SERIAL MSERIAL(LCD_SERIAL_PORT)
-  #else
-    #error "LCD_SERIAL_PORT must be from 0 to 3."
-  #endif
-#endif
+//
+// Serial Ports
+//
 
 #include "MarlinSerial.h"
 #include "MarlinSerialUSB.h"
diff --git a/Marlin/src/HAL/DUE/MarlinSerial.h b/Marlin/src/HAL/DUE/MarlinSerial.h
index b80ae2182312..cee0857d2b11 100644
--- a/Marlin/src/HAL/DUE/MarlinSerial.h
+++ b/Marlin/src/HAL/DUE/MarlinSerial.h
@@ -33,6 +33,21 @@
 #include "../../core/types.h"
 #include "../../core/serial_hook.h"
 
+typedef ForwardSerial1Class< decltype(Serial) > DefaultSerial1;
+typedef ForwardSerial1Class< decltype(Serial1) > DefaultSerial2;
+typedef ForwardSerial1Class< decltype(Serial2) > DefaultSerial3;
+typedef ForwardSerial1Class< decltype(Serial3) > DefaultSerial4;
+extern DefaultSerial1 MSerial0;
+extern DefaultSerial2 MSerial1;
+extern DefaultSerial3 MSerial2;
+extern DefaultSerial4 MSerial3;
+
+#define SERIAL_INDEX_MIN 0
+#define SERIAL_INDEX_MAX 3
+#define EP_SERIAL_PORT(N) customizedSerial##N
+#define USB_SERIAL_PORT(N) customizedSerial##N
+#include "../shared/serial_ports.h"
+
 // Define constants and variables for buffering incoming serial data.  We're
 // using a ring buffer (I think), in which rx_buffer_head is the index of the
 // location to which to write the next incoming character and rx_buffer_tail
diff --git a/Marlin/src/HAL/HC32/HAL.h b/Marlin/src/HAL/HC32/HAL.h
index 3f4ba1461550..f751dea09109 100644
--- a/Marlin/src/HAL/HC32/HAL.h
+++ b/Marlin/src/HAL/HC32/HAL.h
@@ -36,60 +36,12 @@
 
 #include "fastio.h"
 #include "timers.h"
-#include "MarlinSerial.h"
 
 //
 // Serial Ports
 //
-#define _MSERIAL(X) MSerial##X
-#define MSERIAL(X) _MSERIAL(X)
-#define NUM_UARTS 4
-
-#if SERIAL_PORT == -1
-  #error "USB Serial is not supported on HC32F460"
-#elif WITHIN(SERIAL_PORT, 1, NUM_UARTS)
-  #define MYSERIAL1 MSERIAL(SERIAL_PORT)
-#else
-  #define MYSERIAL1 MSERIAL(1) // Dummy port
-  static_assert(false, "SERIAL_PORT must be from 1 to " STRINGIFY(NUM_UARTS) ".")
-#endif
-
-#ifdef SERIAL_PORT_2
-  #if SERIAL_PORT_2 == -1
-    #error "USB Serial is not supported on HC32F460"
-  #elif WITHIN(SERIAL_PORT_2, 1, NUM_UARTS)
-    #define MYSERIAL2 MSERIAL(SERIAL_PORT_2)
-  #else
-    #define MYSERIAL2 MSERIAL(1) // Dummy port
-    static_assert(false, "SERIAL_PORT_2 must be from 1 to " STRINGIFY(NUM_UARTS) ".")
-  #endif
-#endif
 
-#ifdef SERIAL_PORT_3
-  #if SERIAL_PORT_3 == -1
-    #error "USB Serial is not supported on HC32F460"
-  #elif WITHIN(SERIAL_PORT_3, 1, NUM_UARTS)
-    #define MYSERIAL3 MSERIAL(SERIAL_PORT_3)
-  #else
-    #define MYSERIAL3 MSERIAL(1) // Dummy port
-    static_assert(false, "SERIAL_PORT_3 must be from 1 to " STRINGIFY(NUM_UARTS) ".")
-  #endif
-#endif
-
-#ifdef LCD_SERIAL_PORT
-  #if LCD_SERIAL_PORT == -1
-    #error "USB Serial is not supported on HC32F460"
-  #elif WITHIN(LCD_SERIAL_PORT, 1, NUM_UARTS)
-    #define LCD_SERIAL MSERIAL(LCD_SERIAL_PORT)
-  #else
-    #define LCD_SERIAL MSERIAL(1) // Dummy port
-    static_assert(false, "LCD_SERIAL_PORT must be from 1 to " STRINGIFY(NUM_UARTS) ".")
-  #endif
-
-  #if HAS_DGUS_LCD
-    #define LCD_SERIAL_TX_BUFFER_FREE() LCD_SERIAL.availableForWrite()
-  #endif
-#endif
+#include "MarlinSerial.h"
 
 //
 // Emergency Parser
diff --git a/Marlin/src/HAL/HC32/MarlinSerial.h b/Marlin/src/HAL/HC32/MarlinSerial.h
index bb4630eb1d52..1a97805a5120 100644
--- a/Marlin/src/HAL/HC32/MarlinSerial.h
+++ b/Marlin/src/HAL/HC32/MarlinSerial.h
@@ -24,6 +24,14 @@
 #include "../../core/serial_hook.h"
 #include <drivers/usart/Usart.h>
 
+#define SERIAL_INDEX_MIN 1
+#define SERIAL_INDEX_MAX 4
+#include "../shared/serial_ports.h"
+
+#if defined(LCD_SERIAL_PORT) && ANY(HAS_DGUS_LCD, EXTENSIBLE_UI)
+  #define LCD_SERIAL_TX_BUFFER_FREE() LCD_SERIAL.availableForWrite()
+#endif
+
 // Optionally set uart IRQ priority to reduce overflow errors
 //#define UART_RX_IRQ_PRIO 1
 //#define UART_TX_IRQ_PRIO 1
diff --git a/Marlin/src/HAL/LPC1768/HAL.cpp b/Marlin/src/HAL/LPC1768/HAL.cpp
index db9881cdd4ac..55658acb7690 100644
--- a/Marlin/src/HAL/LPC1768/HAL.cpp
+++ b/Marlin/src/HAL/LPC1768/HAL.cpp
@@ -35,8 +35,6 @@
 #include <CDCSerial.h>
 #include <usb/mscuser.h>
 
-DefaultSerial1 USBSerial(false, UsbSerial);
-
 uint32_t MarlinHAL::adc_result = 0;
 pin_t MarlinHAL::adc_pin = 0;
 
diff --git a/Marlin/src/HAL/LPC1768/HAL.h b/Marlin/src/HAL/LPC1768/HAL.h
index 6e0c9cff2f46..9a68cdf748e8 100644
--- a/Marlin/src/HAL/LPC1768/HAL.h
+++ b/Marlin/src/HAL/LPC1768/HAL.h
@@ -38,72 +38,15 @@ extern "C" volatile uint32_t _millis;
 #include "../shared/math_32bit.h"
 #include "../shared/HAL_SPI.h"
 #include "fastio.h"
-#include "MarlinSerial.h"
 
 #include <adc.h>
 #include <pinmapping.h>
-#include <CDCSerial.h>
-
-// ------------------------
-// Serial ports
-// ------------------------
-
-typedef ForwardSerial1Class< decltype(UsbSerial) > DefaultSerial1;
-extern DefaultSerial1 USBSerial;
 
-#define _MSERIAL(X) MSerial##X
-#define MSERIAL(X) _MSERIAL(X)
-
-#if SERIAL_PORT == -1
-  #define MYSERIAL1 USBSerial
-#elif WITHIN(SERIAL_PORT, 0, 3)
-  #define MYSERIAL1 MSERIAL(SERIAL_PORT)
-#else
-  #error "SERIAL_PORT must be from 0 to 3. You can also use -1 if the board supports Native USB."
-#endif
-
-#ifdef SERIAL_PORT_2
-  #if SERIAL_PORT_2 == -1
-    #define MYSERIAL2 USBSerial
-  #elif WITHIN(SERIAL_PORT_2, 0, 3)
-    #define MYSERIAL2 MSERIAL(SERIAL_PORT_2)
-  #else
-    #error "SERIAL_PORT_2 must be from 0 to 3. You can also use -1 if the board supports Native USB."
-  #endif
-#endif
-
-#ifdef SERIAL_PORT_3
-  #if SERIAL_PORT_3 == -1
-    #define MYSERIAL3 USBSerial
-  #elif WITHIN(SERIAL_PORT_3, 0, 3)
-    #define MYSERIAL3 MSERIAL(SERIAL_PORT_3)
-  #else
-    #error "SERIAL_PORT_3 must be from 0 to 3. You can also use -1 if the board supports Native USB."
-  #endif
-#endif
-
-#ifdef MMU_SERIAL_PORT
-  #if MMU_SERIAL_PORT == -1
-    #define MMU_SERIAL USBSerial
-  #elif WITHIN(MMU_SERIAL_PORT, 0, 3)
-    #define MMU_SERIAL MSERIAL(MMU_SERIAL_PORT)
-  #else
-    #error "MMU_SERIAL_PORT must be from 0 to 3. You can also use -1 if the board supports Native USB."
-  #endif
-#endif
+//
+// Serial Ports
+//
 
-#ifdef LCD_SERIAL_PORT
-  #if LCD_SERIAL_PORT == -1
-    #define LCD_SERIAL USBSerial
-  #elif WITHIN(LCD_SERIAL_PORT, 0, 3)
-    #define LCD_SERIAL MSERIAL(LCD_SERIAL_PORT)
-  #else
-    #error "LCD_SERIAL_PORT must be from 0 to 3. You can also use -1 if the board supports Native USB."
-  #endif
-  #if ANY(HAS_DGUS_LCD, EXTENSIBLE_UI)
-    #define LCD_SERIAL_TX_BUFFER_FREE() LCD_SERIAL.available()
-  #endif
-#endif
+#include "MarlinSerial.h"
 
 //
 // Interrupts
diff --git a/Marlin/src/HAL/LPC1768/MarlinSerial.cpp b/Marlin/src/HAL/LPC1768/MarlinSerial.cpp
index f2aecf54a050..291eba68a700 100644
--- a/Marlin/src/HAL/LPC1768/MarlinSerial.cpp
+++ b/Marlin/src/HAL/LPC1768/MarlinSerial.cpp
@@ -25,6 +25,8 @@
 
 #include "../../inc/MarlinConfig.h"
 
+DefaultSerial1 USBSerial(false, UsbSerial);
+
 #if USING_HW_SERIAL0
   MarlinSerial _MSerial0(LPC_UART0);
   MSerialT MSerial0(true, _MSerial0);
diff --git a/Marlin/src/HAL/LPC1768/MarlinSerial.h b/Marlin/src/HAL/LPC1768/MarlinSerial.h
index 2fadd8209bdf..04110e4aff23 100644
--- a/Marlin/src/HAL/LPC1768/MarlinSerial.h
+++ b/Marlin/src/HAL/LPC1768/MarlinSerial.h
@@ -21,6 +21,7 @@
  */
 #pragma once
 
+#include <CDCSerial.h>
 #include <HardwareSerial.h>
 #include <WString.h>
 
@@ -30,6 +31,18 @@
 #endif
 #include "../../core/serial_hook.h"
 
+typedef ForwardSerial1Class< decltype(UsbSerial) > DefaultSerial1;
+extern DefaultSerial1 USBSerial;
+
+#define SERIAL_INDEX_MIN 0
+#define SERIAL_INDEX_MAX 3
+#define USB_SERIAL_PORT(...) USBSerial
+#include "../shared/serial_ports.h"
+
+#if defined(LCD_SERIAL_PORT) && ANY(HAS_DGUS_LCD, EXTENSIBLE_UI)
+  #define LCD_SERIAL_TX_BUFFER_FREE() LCD_SERIAL.available()
+#endif
+
 class MarlinSerial : public HardwareSerial<RX_BUFFER_SIZE, TX_BUFFER_SIZE> {
 public:
   MarlinSerial(LPC_UART_TypeDef *UARTx) : HardwareSerial<RX_BUFFER_SIZE, TX_BUFFER_SIZE>(UARTx) { }
diff --git a/Marlin/src/HAL/NATIVE_SIM/HAL.h b/Marlin/src/HAL/NATIVE_SIM/HAL.h
index 020299fa5d3c..f741d0b246d2 100644
--- a/Marlin/src/HAL/NATIVE_SIM/HAL.h
+++ b/Marlin/src/HAL/NATIVE_SIM/HAL.h
@@ -71,37 +71,10 @@ extern MSerialT serial_stream_2;
 extern MSerialT serial_stream_3;
 
 #define _MSERIAL(X) serial_stream_##X
-#define MSERIAL(X) _MSERIAL(X)
 
-#if WITHIN(SERIAL_PORT, 0, 3)
-  #define MYSERIAL1 MSERIAL(SERIAL_PORT)
-#else
-  #error "SERIAL_PORT must be from 0 to 3. Please update your configuration."
-#endif
-
-#ifdef SERIAL_PORT_2
-  #if WITHIN(SERIAL_PORT_2, 0, 3)
-    #define MYSERIAL2 MSERIAL(SERIAL_PORT_2)
-  #else
-    #error "SERIAL_PORT_2 must be from 0 to 3. Please update your configuration."
-  #endif
-#endif
-
-#ifdef MMU_SERIAL_PORT
-  #if WITHIN(MMU_SERIAL_PORT, 0, 3)
-    #define MMU_SERIAL MSERIAL(MMU_SERIAL_PORT)
-  #else
-    #error "MMU_SERIAL_PORT must be from 0 to 3. Please update your configuration."
-  #endif
-#endif
-
-#ifdef LCD_SERIAL_PORT
-  #if WITHIN(LCD_SERIAL_PORT, 0, 3)
-    #define LCD_SERIAL MSERIAL(LCD_SERIAL_PORT)
-  #else
-    #error "LCD_SERIAL_PORT must be from 0 to 3. Please update your configuration."
-  #endif
-#endif
+#define SERIAL_INDEX_MIN 0
+#define SERIAL_INDEX_MAX 3
+#include "../shared/serial_ports.h"
 
 // ------------------------
 // Interrupts
diff --git a/Marlin/src/HAL/RP2040/HAL.h b/Marlin/src/HAL/RP2040/HAL.h
index fa1a35683e1f..fbd3b61e1ca4 100644
--- a/Marlin/src/HAL/RP2040/HAL.h
+++ b/Marlin/src/HAL/RP2040/HAL.h
@@ -35,73 +35,16 @@
 #include "fastio.h"
 //#include "Servo.h"
 #include "watchdog.h"
-#include "MarlinSerial.h"
 
 #include "../../inc/MarlinConfigPre.h"
 
 #include <stdint.h>
 
-// ------------------------
-// Serial ports
-// ------------------------
-
-#include "../../core/serial_hook.h"
-typedef ForwardSerial1Class< decltype(Serial) > DefaultSerial1;
-extern DefaultSerial1 MSerial0;
-
-#define _MSERIAL(X) MSerial##X
-#define MSERIAL(X) _MSERIAL(X)
-
-#if SERIAL_PORT == -1
-  #define MYSERIAL1 MSerial0
-#elif WITHIN(SERIAL_PORT, 0, 6)
-  #define MYSERIAL1 MSERIAL(SERIAL_PORT)
-#else
-  #error "SERIAL_PORT must be from 0 to 6. You can also use -1 if the board supports Native USB."
-#endif
-
-#ifdef SERIAL_PORT_2
-  #if SERIAL_PORT_2 == -1
-    #define MYSERIAL2 MSerial0
-  #elif WITHIN(SERIAL_PORT_2, 0, 6)
-    #define MYSERIAL2 MSERIAL(SERIAL_PORT_2)
-  #else
-    #error "SERIAL_PORT_2 must be from 0 to 6. You can also use -1 if the board supports Native USB."
-  #endif
-#endif
-
-#ifdef SERIAL_PORT_3
-  #if SERIAL_PORT_3 == -1
-    #define MYSERIAL3 MSerial0
-  #elif WITHIN(SERIAL_PORT_3, 0, 6)
-    #define MYSERIAL3 MSERIAL(SERIAL_PORT_3)
-  #else
-    #error "SERIAL_PORT_3 must be from 0 to 6. You can also use -1 if the board supports Native USB."
-  #endif
-#endif
-
-#ifdef MMU2_SERIAL_PORT
-  #if MMU2_SERIAL_PORT == -1
-    #define MMU2_SERIAL MSerial0
-  #elif WITHIN(MMU2_SERIAL_PORT, 0, 6)
-    #define MMU2_SERIAL MSERIAL(MMU2_SERIAL_PORT)
-  #else
-    #error "MMU2_SERIAL_PORT must be from 0 to 6. You can also use -1 if the board supports Native USB."
-  #endif
-#endif
+//
+// Serial Ports
+//
 
-#ifdef LCD_SERIAL_PORT
-  #if LCD_SERIAL_PORT == -1
-    #define LCD_SERIAL MSerial0
-  #elif WITHIN(LCD_SERIAL_PORT, 0, 6)
-    #define LCD_SERIAL MSERIAL(LCD_SERIAL_PORT)
-  #else
-    #error "LCD_SERIAL_PORT must be from 0 to 6. You can also use -1 if the board supports Native USB."
-  #endif
-  #if HAS_DGUS_LCD
-    #define SERIAL_GET_TX_BUFFER_FREE() LCD_SERIAL.availableForWrite()
-  #endif
-#endif
+#include "MarlinSerial.h"
 
 // ------------------------
 // Defines
diff --git a/Marlin/src/HAL/RP2040/MarlinSerial.h b/Marlin/src/HAL/RP2040/MarlinSerial.h
index c5924c90621d..b0db3167fab3 100644
--- a/Marlin/src/HAL/RP2040/MarlinSerial.h
+++ b/Marlin/src/HAL/RP2040/MarlinSerial.h
@@ -29,24 +29,22 @@
 
 #include "../../core/serial_hook.h"
 
+typedef ForwardSerial1Class< decltype(Serial) > DefaultSerial1;
+extern DefaultSerial1 MSerial0;
+typedef ForwardSerial1Class<decltype(SerialUSB)> USBSerialType;
+extern USBSerialType USBSerial;
+
 #define Serial0 Serial
 #define _DECLARE_SERIAL(X) \
   typedef ForwardSerial1Class<decltype(Serial##X)> DefaultSerial##X; \
   extern DefaultSerial##X MSerial##X
 #define DECLARE_SERIAL(X) _DECLARE_SERIAL(X)
 
-typedef ForwardSerial1Class<decltype(SerialUSB)> USBSerialType;
-extern USBSerialType USBSerial;
-
-#define _MSERIAL(X) MSerial##X
-#define MSERIAL(X) _MSERIAL(X)
+#define SERIAL_INDEX_MIN 0
+#define SERIAL_INDEX_MAX 6
+#define USB_SERIAL_PORT(...) MSerial0
+#include "../shared/serial_ports.h"
 
-#if SERIAL_PORT == -1
- // #define MYSERIAL1 USBSerial this is already done in the HAL
-#elif WITHIN(SERIAL_PORT, 0, 3)
- #define MYSERIAL1 MSERIAL(SERIAL_PORT)
-  DECLARE_SERIAL(SERIAL_PORT);
-#else
-  #error "SERIAL_PORT must be from 0 to 3, or -1 for Native USB."
+#if defined(LCD_SERIAL_PORT) && ANY(HAS_DGUS_LCD, EXTENSIBLE_UI)
+  #define SERIAL_GET_TX_BUFFER_FREE() LCD_SERIAL.availableForWrite()
 #endif
-
diff --git a/Marlin/src/HAL/SAMD21/HAL.h b/Marlin/src/HAL/SAMD21/HAL.h
index 63beb29cf145..e95f0e6f70b0 100644
--- a/Marlin/src/HAL/SAMD21/HAL.h
+++ b/Marlin/src/HAL/SAMD21/HAL.h
@@ -36,11 +36,11 @@
 // ------------------------
 // Serial ports
 // ------------------------
+
 #include "../../core/serial_hook.h"
 typedef ForwardSerial1Class< decltype(SerialUSB) > DefaultSerial1;
 extern DefaultSerial1 MSerialUSB;
 
-// Serial ports
 typedef ForwardSerial1Class< decltype(Serial1) > DefaultSerial2;
 typedef ForwardSerial1Class< decltype(Serial2) > DefaultSerial3;
 
@@ -51,43 +51,10 @@ extern DefaultSerial3 MSerial1;
 #define _MSERIAL(X) __MSERIAL(X)
 #define MSERIAL(X) _MSERIAL(INCREMENT(X))
 
-#if WITHIN(SERIAL_PORT, 0, 1)
-  #define MYSERIAL1 MSERIAL(SERIAL_PORT)
-#elif SERIAL_PORT == -1
-  #define MYSERIAL1 MSerialUSB
-#else
-  #error "SERIAL_PORT must be -1 (Native USB only)."
-#endif
-
-#ifdef SERIAL_PORT_2
-  #if WITHIN(SERIAL_PORT_2, 0, 1)
-    #define MYSERIAL2 MSERIAL(SERIAL_PORT)
-  #elif SERIAL_PORT_2 == -1
-    #define MYSERIAL2 MSerialUSB
-  #else
-    #error "SERIAL_PORT_2 must be -1 (Native USB only)."
-  #endif
-#endif
-
-#ifdef MMU_SERIAL_PORT
-  #if WITHIN(MMU_SERIAL_PORT, 0, 1)
-    #define MMU_SERIAL MSERIAL(SERIAL_PORT)
-  #elif MMU_SERIAL_PORT == -1
-    #define MMU_SERIAL MSerialUSB
-  #else
-    #error "MMU_SERIAL_PORT must be -1 (Native USB only)."
-  #endif
-#endif
-
-#ifdef LCD_SERIAL_PORT
-  #if WITHIN(LCD_SERIAL_PORT, 0, 1)
-    #define LCD_SERIAL MSERIAL(SERIAL_PORT)
-  #elif LCD_SERIAL_PORT == -1
-    #define LCD_SERIAL MSerialUSB
-  #else
-    #error "LCD_SERIAL_PORT must be -1 (Native USB only)."
-  #endif
-#endif
+#define SERIAL_INDEX_MIN 0
+#define SERIAL_INDEX_MAX 1
+#define USB_SERIAL_PORT(...) MSerialUSB
+#include "../shared/serial_ports.h"
 
 typedef int8_t pin_t;
 
diff --git a/Marlin/src/HAL/SAMD51/HAL.h b/Marlin/src/HAL/SAMD51/HAL.h
index 7655f82da18e..51fed64e35c8 100644
--- a/Marlin/src/HAL/SAMD51/HAL.h
+++ b/Marlin/src/HAL/SAMD51/HAL.h
@@ -34,72 +34,7 @@
 
 #ifdef ADAFRUIT_GRAND_CENTRAL_M4
   #include "MarlinSerial_AGCM4.h"
-
-  // Serial ports
-  typedef ForwardSerial1Class< decltype(Serial) > DefaultSerial1;
-  typedef ForwardSerial1Class< decltype(Serial1) > DefaultSerial2;
-  typedef ForwardSerial1Class< decltype(Serial2) > DefaultSerial3;
-  typedef ForwardSerial1Class< decltype(Serial3) > DefaultSerial4;
-  typedef ForwardSerial1Class< decltype(Serial4) > DefaultSerial5;
-  extern DefaultSerial1 MSerial0;
-  extern DefaultSerial2 MSerial1;
-  extern DefaultSerial3 MSerial2;
-  extern DefaultSerial4 MSerial3;
-  extern DefaultSerial5 MSerial4;
-
-  #define __MSERIAL(X) MSerial##X
-  #define _MSERIAL(X) __MSERIAL(X)
-  #define MSERIAL(X) _MSERIAL(INCREMENT(X))
-
-  #if SERIAL_PORT == -1
-    #define MYSERIAL1 MSerial0
-  #elif WITHIN(SERIAL_PORT, 0, 3)
-    #define MYSERIAL1 MSERIAL(SERIAL_PORT)
-  #else
-    #error "SERIAL_PORT must be from 0 to 3. You can also use -1 if the board supports Native USB."
-  #endif
-
-  #ifdef SERIAL_PORT_2
-    #if SERIAL_PORT_2 == -1
-      #define MYSERIAL2 MSerial0
-    #elif WITHIN(SERIAL_PORT_2, 0, 3)
-      #define MYSERIAL2 MSERIAL(SERIAL_PORT_2)
-    #else
-      #error "SERIAL_PORT_2 must be from 0 to 3. You can also use -1 if the board supports Native USB."
-    #endif
-  #endif
-
-  #ifdef SERIAL_PORT_3
-    #if SERIAL_PORT_3 == -1
-      #define MYSERIAL3 MSerial0
-    #elif WITHIN(SERIAL_PORT_3, 0, 3)
-      #define MYSERIAL3 MSERIAL(SERIAL_PORT_3)
-    #else
-      #error "SERIAL_PORT_3 must be from 0 to 3. You can also use -1 if the board supports Native USB."
-    #endif
-  #endif
-
-  #ifdef MMU_SERIAL_PORT
-    #if MMU_SERIAL_PORT == -1
-      #define MMU_SERIAL MSerial0
-    #elif WITHIN(MMU_SERIAL_PORT, 0, 3)
-      #define MMU_SERIAL MSERIAL(MMU_SERIAL_PORT)
-    #else
-      #error "MMU_SERIAL_PORT must be from 0 to 3. You can also use -1 if the board supports Native USB."
-    #endif
-  #endif
-
-  #ifdef LCD_SERIAL_PORT
-    #if LCD_SERIAL_PORT == -1
-      #define LCD_SERIAL MSerial0
-    #elif WITHIN(LCD_SERIAL_PORT, 0, 3)
-      #define LCD_SERIAL MSERIAL(LCD_SERIAL_PORT)
-    #else
-      #error "LCD_SERIAL_PORT must be from 0 to 3. You can also use -1 if the board supports Native USB."
-    #endif
-  #endif
-
-#endif // ADAFRUIT_GRAND_CENTRAL_M4
+#endif
 
 typedef int8_t pin_t;
 
diff --git a/Marlin/src/HAL/SAMD51/MarlinSerial_AGCM4.h b/Marlin/src/HAL/SAMD51/MarlinSerial_AGCM4.h
index 1044d9fcd0ef..075ec717f32e 100644
--- a/Marlin/src/HAL/SAMD51/MarlinSerial_AGCM4.h
+++ b/Marlin/src/HAL/SAMD51/MarlinSerial_AGCM4.h
@@ -32,3 +32,24 @@ typedef Serial1Class<Uart> UartT;
 extern UartT Serial2;
 extern UartT Serial3;
 extern UartT Serial4;
+
+// Serial ports
+typedef ForwardSerial1Class< decltype(Serial) > DefaultSerial1;
+typedef ForwardSerial1Class< decltype(Serial1) > DefaultSerial2;
+typedef ForwardSerial1Class< decltype(Serial2) > DefaultSerial3;
+typedef ForwardSerial1Class< decltype(Serial3) > DefaultSerial4;
+typedef ForwardSerial1Class< decltype(Serial4) > DefaultSerial5;
+extern DefaultSerial1 MSerial0;
+extern DefaultSerial2 MSerial1;
+extern DefaultSerial3 MSerial2;
+extern DefaultSerial4 MSerial3;
+extern DefaultSerial5 MSerial4;
+
+#define __MSERIAL(X) MSerial##X
+#define _MSERIAL(X) __MSERIAL(X)
+#define MSERIAL(X) _MSERIAL(INCREMENT(X))
+
+#define SERIAL_INDEX_MIN 0
+#define SERIAL_INDEX_MAX 3
+#define USB_SERIAL_PORT(...) MSerial0
+#include "../shared/serial_ports.h"
diff --git a/Marlin/src/HAL/STM32/HAL.h b/Marlin/src/HAL/STM32/HAL.h
index eab31be265e3..f43413fcd919 100644
--- a/Marlin/src/HAL/STM32/HAL.h
+++ b/Marlin/src/HAL/STM32/HAL.h
@@ -30,7 +30,6 @@
 #include "temp_soc.h"
 #include "fastio.h"
 #include "Servo.h"
-#include "MarlinSerial.h"
 
 #include "../../inc/MarlinConfigPre.h"
 
@@ -43,87 +42,11 @@
 #define CPU_ST7920_DELAY_2  40
 #define CPU_ST7920_DELAY_3 340
 
-// ------------------------
-// Serial ports
-// ------------------------
-#ifdef USBCON
-  #include <USBSerial.h>
-  #include "../../core/serial_hook.h"
-  typedef ForwardSerial1Class< decltype(SerialUSB) > DefaultSerial1;
-  extern DefaultSerial1 MSerialUSB;
-#endif
-
-#define _MSERIAL(X) MSerial##X
-#define MSERIAL(X) _MSERIAL(X)
-
-#if WITHIN(SERIAL_PORT, 1, 9)
-  #define MYSERIAL1 MSERIAL(SERIAL_PORT)
-#elif !defined(USBCON)
-  #error "SERIAL_PORT must be from 1 to 9."
-#elif SERIAL_PORT == -1
-  #define MYSERIAL1 MSerialUSB
-#else
-  #error "SERIAL_PORT must be from 1 to 9, or -1 for Native USB."
-#endif
-
-#ifdef SERIAL_PORT_2
-  #if WITHIN(SERIAL_PORT_2, 1, 9)
-    #define MYSERIAL2 MSERIAL(SERIAL_PORT_2)
-  #elif !defined(USBCON)
-    #error "SERIAL_PORT_2 must be from 1 to 9."
-  #elif SERIAL_PORT_2 == -1
-    #define MYSERIAL2 MSerialUSB
-  #else
-    #error "SERIAL_PORT_2 must be from 1 to 9, or -1 for Native USB."
-  #endif
-#endif
-
-#ifdef SERIAL_PORT_3
-  #if WITHIN(SERIAL_PORT_3, 1, 9)
-    #define MYSERIAL3 MSERIAL(SERIAL_PORT_3)
-  #elif !defined(USBCON)
-    #error "SERIAL_PORT_3 must be from 1 to 9."
-  #elif SERIAL_PORT_3 == -1
-    #define MYSERIAL3 MSerialUSB
-  #else
-    #error "SERIAL_PORT_3 must be from 1 to 9, or -1 for Native USB."
-  #endif
-#endif
-
-#ifdef MMU_SERIAL_PORT
-  #if WITHIN(MMU_SERIAL_PORT, 1, 9)
-    #define MMU_SERIAL MSERIAL(MMU_SERIAL_PORT)
-  #elif !defined(USBCON)
-    #error "MMU_SERIAL_PORT must be from 1 to 9."
-  #elif MMU_SERIAL_PORT == -1
-    #define MMU_SERIAL MSerialUSB
-  #else
-    #error "MMU_SERIAL_PORT must be from 1 to 9, or -1 for Native USB."
-  #endif
-#endif
-
-#ifdef LCD_SERIAL_PORT
-  #if WITHIN(LCD_SERIAL_PORT, 1, 9)
-    #define LCD_SERIAL MSERIAL(LCD_SERIAL_PORT)
-  #elif !defined(USBCON)
-    #error "LCD_SERIAL_PORT must be from 1 to 9."
-  #elif LCD_SERIAL_PORT == -1
-    #define LCD_SERIAL MSerialUSB
-  #else
-    #error "LCD_SERIAL_PORT must be from 1 to 9, or -1 for Native USB."
-  #endif
-  #if ANY(HAS_DGUS_LCD, EXTENSIBLE_UI)
-    #define LCD_SERIAL_TX_BUFFER_FREE() LCD_SERIAL.availableForWrite()
-  #endif
-#endif
+//
+// Serial Ports
+//
 
-#ifdef RS485_SERIAL_PORT
-  #if WITHIN(RS485_SERIAL_PORT, 1, 9)
-    #define RS485_SERIAL MSERIAL(RS485_SERIAL_PORT)
-  #else
-    #error "RS485_SERIAL_PORT must be from 1 to 9."
-  #endif
-#endif
+#include "MarlinSerial.h"
 
 /**
  * TODO: review this to return 1 for pins that are not analog input
diff --git a/Marlin/src/HAL/STM32/MarlinSerial.h b/Marlin/src/HAL/STM32/MarlinSerial.h
index d9311a98da86..73ab77d8d484 100644
--- a/Marlin/src/HAL/STM32/MarlinSerial.h
+++ b/Marlin/src/HAL/STM32/MarlinSerial.h
@@ -33,6 +33,21 @@
 
 #include "../../core/serial_hook.h"
 
+#ifdef USBCON
+  #include <USBSerial.h>
+  typedef ForwardSerial1Class< decltype(SerialUSB) > DefaultSerial1;
+  extern DefaultSerial1 MSerialUSB;
+  #define USB_SERIAL_PORT(...) MSerialUSB
+#endif
+
+#define SERIAL_INDEX_MIN 1
+#define SERIAL_INDEX_MAX 9
+#include "../shared/serial_ports.h"
+
+#if defined(LCD_SERIAL_PORT) && ANY(HAS_DGUS_LCD, EXTENSIBLE_UI)
+  #define LCD_SERIAL_TX_BUFFER_FREE() LCD_SERIAL.availableForWrite()
+#endif
+
 #if ENABLED(SERIAL_DMA)
 
   struct MarlinSerial : public HAL_HardwareSerial {
diff --git a/Marlin/src/HAL/STM32F1/HAL.h b/Marlin/src/HAL/STM32F1/HAL.h
index e80ced866da1..daf94dceb56b 100644
--- a/Marlin/src/HAL/STM32F1/HAL.h
+++ b/Marlin/src/HAL/STM32F1/HAL.h
@@ -43,8 +43,6 @@
   #include "msc_sd.h"
 #endif
 
-#include "MarlinSerial.h"
-
 // ------------------------
 // Defines
 // ------------------------
@@ -64,95 +62,11 @@
   #endif
 #endif
 
-// ------------------------
-// Serial ports
-// ------------------------
-
-#ifdef SERIAL_USB
-  typedef ForwardSerial1Class< USBSerial > DefaultSerial1;
-  extern DefaultSerial1 MSerial0;
-  #if HAS_SD_HOST_DRIVE
-    #define UsbSerial MarlinCompositeSerial
-  #else
-    #define UsbSerial MSerial0
-  #endif
-#endif
-
-#define _MSERIAL(X) MSerial##X
-#define MSERIAL(X) _MSERIAL(X)
-
-#if ANY(STM32_HIGH_DENSITY, STM32_XL_DENSITY)
-  #define NUM_UARTS 5
-#else
-  #define NUM_UARTS 3
-#endif
-
-#if SERIAL_PORT == -1
-  #define MYSERIAL1 UsbSerial
-#elif WITHIN(SERIAL_PORT, 1, NUM_UARTS)
-  #define MYSERIAL1 MSERIAL(SERIAL_PORT)
-#else
-  #define MYSERIAL1 MSERIAL(1) // dummy port
-  static_assert(false, "SERIAL_PORT must be from 1 to " STRINGIFY(NUM_UARTS) ". You can also use -1 if the board supports Native USB.")
-#endif
-
-#ifdef SERIAL_PORT_2
-  #if SERIAL_PORT_2 == -1
-    #define MYSERIAL2 UsbSerial
-  #elif WITHIN(SERIAL_PORT_2, 1, NUM_UARTS)
-    #define MYSERIAL2 MSERIAL(SERIAL_PORT_2)
-  #else
-    #define MYSERIAL2 MSERIAL(1) // dummy port
-    static_assert(false, "SERIAL_PORT_2 must be from 1 to " STRINGIFY(NUM_UARTS) ". You can also use -1 if the board supports Native USB.")
-  #endif
-#endif
-
-#ifdef SERIAL_PORT_3
-  #if SERIAL_PORT_3 == -1
-    #define MYSERIAL3 UsbSerial
-  #elif WITHIN(SERIAL_PORT_3, 1, NUM_UARTS)
-    #define MYSERIAL3 MSERIAL(SERIAL_PORT_3)
-  #else
-    #define MYSERIAL3 MSERIAL(1) // dummy port
-    static_assert(false, "SERIAL_PORT_3 must be from 1 to " STRINGIFY(NUM_UARTS) ". You can also use -1 if the board supports Native USB.")
-  #endif
-#endif
-
-#ifdef MMU_SERIAL_PORT
-  #if MMU_SERIAL_PORT == -1
-    #define MMU_SERIAL UsbSerial
-  #elif WITHIN(MMU_SERIAL_PORT, 1, NUM_UARTS)
-    #define MMU_SERIAL MSERIAL(MMU_SERIAL_PORT)
-  #else
-    #define MMU_SERIAL MSERIAL(1) // dummy port
-    static_assert(false, "MMU_SERIAL_PORT must be from 1 to " STRINGIFY(NUM_UARTS) ". You can also use -1 if the board supports Native USB.")
-  #endif
-#endif
-
-#ifdef LCD_SERIAL_PORT
-  #if LCD_SERIAL_PORT == -1
-    #define LCD_SERIAL UsbSerial
-  #elif WITHIN(LCD_SERIAL_PORT, 1, NUM_UARTS)
-    #define LCD_SERIAL MSERIAL(LCD_SERIAL_PORT)
-  #else
-    #define LCD_SERIAL MSERIAL(1) // dummy port
-    static_assert(false, "LCD_SERIAL_PORT must be from 1 to " STRINGIFY(NUM_UARTS) ". You can also use -1 if the board supports Native USB.")
-  #endif
-  #if ANY(HAS_DGUS_LCD, EXTENSIBLE_UI)
-    #define LCD_SERIAL_TX_BUFFER_FREE() LCD_SERIAL.availableForWrite()
-  #endif
-#endif
+//
+// Serial Ports
+//
 
-#ifdef RS485_SERIAL_PORT
-  #if RS485_SERIAL_PORT == -1
-    #define RS485_SERIAL UsbSerial
-  #elif WITHIN(RS485_SERIAL_PORT, 1, NUM_UARTS)
-    #define RS485_SERIAL MSERIAL(RS485_SERIAL_PORT)
-  #else
-    #define RS485_SERIAL MSERIAL(1) // dummy port
-    static_assert(false, "RS485_SERIAL_PORT must be from 1 to " STRINGIFY(NUM_UARTS) ".")
-  #endif
-#endif
+#include "MarlinSerial.h"
 
 /**
  * TODO: review this to return 1 for pins that are not analog input
diff --git a/Marlin/src/HAL/STM32F1/MarlinSerial.h b/Marlin/src/HAL/STM32F1/MarlinSerial.h
index 53bcd4847638..c2dc5bd57145 100644
--- a/Marlin/src/HAL/STM32F1/MarlinSerial.h
+++ b/Marlin/src/HAL/STM32F1/MarlinSerial.h
@@ -28,6 +28,29 @@
 #include "../../inc/MarlinConfigPre.h"
 #include "../../core/serial_hook.h"
 
+#ifdef SERIAL_USB
+  typedef ForwardSerial1Class< USBSerial > DefaultSerial1;
+  extern DefaultSerial1 MSerial0;
+  #if HAS_SD_HOST_DRIVE
+    #define UsbSerial MarlinCompositeSerial
+  #else
+    #define UsbSerial MSerial0
+  #endif
+#endif
+
+#define SERIAL_INDEX_MIN 1
+#if ANY(STM32_HIGH_DENSITY, STM32_XL_DENSITY)
+  #define SERIAL_INDEX_MAX 5
+#else
+  #define SERIAL_INDEX_MAX 3
+#endif
+#define USB_SERIAL_PORT(...) UsbSerial
+#include "../shared/serial_ports.h"
+
+#if defined(LCD_SERIAL_PORT) && ANY(HAS_DGUS_LCD, EXTENSIBLE_UI)
+  #define LCD_SERIAL_TX_BUFFER_FREE() LCD_SERIAL.availableForWrite()
+#endif
+
 // Increase priority of serial interrupts, to reduce overflow errors
 #define UART_IRQ_PRIO 1
 
diff --git a/Marlin/src/HAL/TEENSY31_32/HAL.h b/Marlin/src/HAL/TEENSY31_32/HAL.h
index 659fcb72e56e..03610c65f83f 100644
--- a/Marlin/src/HAL/TEENSY31_32/HAL.h
+++ b/Marlin/src/HAL/TEENSY31_32/HAL.h
@@ -64,17 +64,10 @@
 typedef ForwardSerial1Class<decltype(SerialUSB)> USBSerialType;
 extern USBSerialType USBSerial;
 
-#define _MSERIAL(X) MSerial##X
-#define MSERIAL(X) _MSERIAL(X)
-
-#if SERIAL_PORT == -1
-  #define MYSERIAL1 USBSerial
-#elif WITHIN(SERIAL_PORT, 0, 3)
-  DECLARE_SERIAL(SERIAL_PORT);
-  #define MYSERIAL1 MSERIAL(SERIAL_PORT)
-#else
-  #error "The required SERIAL_PORT must be from 0 to 3, or -1 for Native USB."
-#endif
+#define SERIAL_INDEX_MIN 0
+#define SERIAL_INDEX_MAX 3
+#define USB_SERIAL_PORT(...) USBSerial
+#include "../shared/serial_ports.h"
 
 // ------------------------
 // Types
diff --git a/Marlin/src/HAL/TEENSY35_36/HAL.h b/Marlin/src/HAL/TEENSY35_36/HAL.h
index 44eafe5e6d1b..0f229000d4a4 100644
--- a/Marlin/src/HAL/TEENSY35_36/HAL.h
+++ b/Marlin/src/HAL/TEENSY35_36/HAL.h
@@ -70,17 +70,10 @@
 typedef ForwardSerial1Class<decltype(SerialUSB)> USBSerialType;
 extern USBSerialType USBSerial;
 
-#define _MSERIAL(X) MSerial##X
-#define MSERIAL(X) _MSERIAL(X)
-
-#if SERIAL_PORT == -1
-  #define MYSERIAL1 USBSerial
-#elif WITHIN(SERIAL_PORT, 0, 3)
-  #define MYSERIAL1 MSERIAL(SERIAL_PORT)
-  DECLARE_SERIAL(SERIAL_PORT);
-#else
-  #error "SERIAL_PORT must be from 0 to 3, or -1 for Native USB."
-#endif
+#define SERIAL_INDEX_MIN 0
+#define SERIAL_INDEX_MAX 3
+#define USB_SERIAL_PORT(...) USBSerial
+#include "../shared/serial_ports.h"
 
 // ------------------------
 // Types
diff --git a/Marlin/src/HAL/TEENSY40_41/HAL.h b/Marlin/src/HAL/TEENSY40_41/HAL.h
index 7fa285ae621c..f884db6684dc 100644
--- a/Marlin/src/HAL/TEENSY40_41/HAL.h
+++ b/Marlin/src/HAL/TEENSY40_41/HAL.h
@@ -78,41 +78,11 @@
 typedef ForwardSerial1Class<decltype(SerialUSB)> USBSerialType;
 extern USBSerialType USBSerial;
 
-#define _MSERIAL(X) MSerial##X
-#define MSERIAL(X) _MSERIAL(X)
-
-#if SERIAL_PORT == -1
-  #define MYSERIAL1 USBSerial
-#elif WITHIN(SERIAL_PORT, 0, 8)
-  DECLARE_SERIAL(SERIAL_PORT);
-  #define MYSERIAL1 MSERIAL(SERIAL_PORT)
-#else
-  #error "The required SERIAL_PORT must be from 0 to 8, or -1 for Native USB."
-#endif
-
-#ifdef SERIAL_PORT_2
-  #if SERIAL_PORT_2 == -1
-    #define MYSERIAL2 USBSerial
-  #elif SERIAL_PORT_2 == -2
-    #define MYSERIAL2 ethernet.telnetClient
-  #elif WITHIN(SERIAL_PORT_2, 0, 8)
-    DECLARE_SERIAL(SERIAL_PORT_2);
-    #define MYSERIAL2 MSERIAL(SERIAL_PORT_2)
-  #else
-    #error "SERIAL_PORT_2 must be from 0 to 8, or -1 for Native USB, or -2 for Ethernet."
-  #endif
-#endif
-
-#ifdef SERIAL_PORT_3
-  #if SERIAL_PORT_3 == -1
-    #define MYSERIAL3 USBSerial
-  #elif WITHIN(SERIAL_PORT_3, 0, 8)
-    DECLARE_SERIAL(SERIAL_PORT_3);
-    #define MYSERIAL3 MSERIAL(SERIAL_PORT_3)
-  #else
-    #error "SERIAL_PORT_3 must be from 0 to 8, or -1 for Native USB."
-  #endif
-#endif
+#define SERIAL_INDEX_MIN 0
+#define SERIAL_INDEX_MAX 8
+#define USB_SERIAL_PORT(...) USBSerial
+#define ETH_SERIAL_PORT(...) ethernet.telnetClient
+#include "../shared/serial_ports.h"
 
 // ------------------------
 // Types
diff --git a/Marlin/src/HAL/shared/serial_ports.h b/Marlin/src/HAL/shared/serial_ports.h
new file mode 100644
index 000000000000..66ff57594ed8
--- /dev/null
+++ b/Marlin/src/HAL/shared/serial_ports.h
@@ -0,0 +1,184 @@
+/**
+ * Marlin 3D Printer Firmware
+ * Copyright (c) 2025 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
+ *
+ * Based on Sprinter and grbl.
+ * Copyright (c) 2011 Camiel Gubbels / Erik van der Zalm
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ */
+#pragma once
+
+/**
+ * serial_ports.h - Define Marlin serial port macros and optionally declare ports
+ *
+ * This header defines one or more of the serial ports...
+ *   - MYSERIAL1/2/3 ..... for host devices
+ *   - MMU_SERIAL ........ for Multi-Material color changers
+ *   - LCD_SERIAL ........ for serial LCDs
+ *   - RS485_SERIAL ...... for CAN bus devices
+ *
+ * Before including this header define the following macros:
+ *   - SERIAL_INDEX_MIN, SERIAL_INDEX_MAX to provide the valid range of serial port indexes.
+ *   - _MSERIAL(X) and MSERIAL(X) to provide the instance name of Serial Port X. (Default: MSerial##X)
+ *   - EP_SERIAL_PORT(X) to provide the instance name of Emergency Parser serial port X (if it is special).
+ *   - USB_SERIAL_PORT(X) to provide the instance name of the USB serial port (if any).
+ *   - ETH_SERIAL_PORT(X) to provide the instance name of the Ethernet serial port (if any).
+ *   - DECLARE_SERIAL(X) to declare standard a serial port with the given index.
+ */
+
+#ifndef _MSERIAL
+  #define _MSERIAL(X) MSerial##X
+#endif
+#ifndef MSERIAL
+  #define MSERIAL(X) _MSERIAL(X)
+#endif
+
+#define INDEX_RANGE_MSG " must be from " STRINGIFY(SERIAL_INDEX_MIN) " to " STRINGIFY(SERIAL_INDEX_MAX)
+
+//
+// SERIAL_PORT => MYSERIAL1
+//
+
+#if defined(EP_SERIAL_PORT) && ENABLED(EMERGENCY_PARSER)
+  #define MYSERIAL1 EP_SERIAL_PORT(1)
+#elif WITHIN(SERIAL_PORT, SERIAL_INDEX_MIN, SERIAL_INDEX_MAX)
+  #define MYSERIAL1 MSERIAL(SERIAL_PORT)
+  #ifdef DECLARE_SERIAL
+    DECLARE_SERIAL(SERIAL_PORT);
+  #endif
+#elif !defined(USB_SERIAL_PORT) && !defined(ETH_SERIAL_PORT)
+  static_assert(false, "SERIAL_PORT" INDEX_RANGE_MSG ".");
+#elif SERIAL_PORT == -1
+  #define MYSERIAL1 USB_SERIAL_PORT(1)
+#elif !defined(ETH_SERIAL_PORT)
+  static_assert(false, "SERIAL_PORT" INDEX_RANGE_MSG ", or -1 for Native USB.");
+#elif SERIAL_PORT == -2
+  #define MYSERIAL1 ETH_SERIAL_PORT(1)
+#else
+  static_assert(false, "SERIAL_PORT" INDEX_RANGE_MSG ", -1 for Native USB, or -2 for Ethernet.");
+#endif
+#ifndef MYSERIAL1
+  #define MYSERIAL1 _MSERIAL(1) // Dummy port
+#endif
+
+//
+// SERIAL_PORT_2 => MYSERIAL2
+//
+
+#ifdef SERIAL_PORT_2
+  #if defined(EP_SERIAL_PORT) && ENABLED(EMERGENCY_PARSER)
+    #define MYSERIAL2 EP_SERIAL_PORT(2)
+  #elif WITHIN(SERIAL_PORT_2, SERIAL_INDEX_MIN, SERIAL_INDEX_MAX)
+    #define MYSERIAL2 MSERIAL(SERIAL_PORT_2)
+    #ifdef DECLARE_SERIAL
+      DECLARE_SERIAL(SERIAL_PORT_2);
+    #endif
+  #elif !defined(USB_SERIAL_PORT) && !defined(ETH_SERIAL_PORT)
+    static_assert(false, "SERIAL_PORT_2" INDEX_RANGE_MSG ".");
+  #elif SERIAL_PORT_2 == -1
+    #define MYSERIAL2 USB_SERIAL_PORT(2)
+  #elif !defined(ETH_SERIAL_PORT)
+    static_assert(false, "SERIAL_PORT_2" INDEX_RANGE_MSG ", or -1 for Native USB.");
+  #elif SERIAL_PORT == -2
+    #define MYSERIAL2 ETH_SERIAL_PORT(2)
+  #else
+    static_assert(false, "SERIAL_PORT" INDEX_RANGE_MSG ", -1 for Native USB, or -2 for Ethernet.");
+  #endif
+  #ifndef MYSERIAL2
+    #define MYSERIAL2 _MSERIAL(1) // Dummy port
+  #endif
+#endif
+
+//
+// SERIAL_PORT_3 => MYSERIAL3
+//
+
+#ifdef SERIAL_PORT_3
+  #if defined(EP_SERIAL_PORT) && ENABLED(EMERGENCY_PARSER)
+    #define MYSERIAL3 EP_SERIAL_PORT(3)
+  #elif WITHIN(SERIAL_PORT_3, SERIAL_INDEX_MIN, SERIAL_INDEX_MAX)
+    #define MYSERIAL3 MSERIAL(SERIAL_PORT_3)
+    #ifdef DECLARE_SERIAL
+      DECLARE_SERIAL(SERIAL_PORT_3);
+    #endif
+  #elif !defined(USB_SERIAL_PORT) && !defined(ETH_SERIAL_PORT)
+    static_assert(false, "SERIAL_PORT_3" INDEX_RANGE_MSG ".");
+  #elif SERIAL_PORT_3 == -1
+    #define MYSERIAL3 USB_SERIAL_PORT(3)
+  #elif !defined(ETH_SERIAL_PORT)
+    static_assert(false, "SERIAL_PORT_3" INDEX_RANGE_MSG ", or -1 for Native USB.");
+  #elif SERIAL_PORT == -2
+    #define MYSERIAL3 ETH_SERIAL_PORT(3)
+  #else
+    static_assert(false, "SERIAL_PORT" INDEX_RANGE_MSG ", -1 for Native USB, or -2 for Ethernet.");
+  #endif
+  #ifndef MYSERIAL3
+    #define MYSERIAL3 _MSERIAL(1) // Dummy port
+  #endif
+#endif
+
+//
+// MMU_SERIAL_PORT => MMU_SERIAL
+//
+
+#ifdef MMU_SERIAL_PORT
+  #if WITHIN(MMU_SERIAL_PORT, SERIAL_INDEX_MIN, SERIAL_INDEX_MAX)
+    #define MMU_SERIAL MSERIAL(MMU_SERIAL_PORT)
+    #ifdef DECLARE_SERIAL
+      DECLARE_SERIAL(MMU_SERIAL_PORT);
+    #endif
+  #else
+    static_assert(false, "MMU_SERIAL_PORT" INDEX_RANGE_MSG ".");
+    #define MMU_SERIAL _MSERIAL(1) // Dummy port
+  #endif
+#endif
+
+//
+// LCD_SERIAL_PORT => LCD_SERIAL
+//
+
+#ifdef LCD_SERIAL_PORT
+  #if WITHIN(LCD_SERIAL_PORT, SERIAL_INDEX_MIN, SERIAL_INDEX_MAX)
+    #define LCD_SERIAL MSERIAL(LCD_SERIAL_PORT)
+    #ifdef DECLARE_SERIAL
+      DECLARE_SERIAL(LCD_SERIAL_PORT);
+    #endif
+  #else
+    static_assert(false, "LCD_SERIAL_PORT" INDEX_RANGE_MSG ".");
+    #define LCD_SERIAL _MSERIAL(1) // Dummy port
+  #endif
+#endif
+
+//
+// RS485_SERIAL_PORT => RS485_SERIAL
+//
+
+#ifdef RS485_SERIAL_PORT
+  #if WITHIN(RS485_SERIAL_PORT, SERIAL_INDEX_MIN, SERIAL_INDEX_MAX)
+    #define RS485_SERIAL MSERIAL(RS485_SERIAL_PORT)
+    #ifdef DECLARE_SERIAL
+      DECLARE_SERIAL(RS485_SERIAL_PORT);
+    #endif
+  #else
+    static_assert(false, "RS485_SERIAL_PORT" INDEX_RANGE_MSG ".");
+    #define RS485_SERIAL _MSERIAL(1) // Dummy port
+  #endif
+#endif
+
+#undef DECLARE_SERIAL
+#undef SERIAL_INDEX_MIN
+#undef SERIAL_INDEX_MAX
+#undef INDEX_RANGE_MSG