Use names SerialUSB1 & SerialUSB2 for extra USB serial ports

keywords.txt

 Serial6	KEYWORD1
 Serial7	KEYWORD1
 Serial8	KEYWORD1
+SerialUSB1	KEYWORD1
+SerialUSB2	KEYWORD1
 setRX	KEYWORD2
 setTX	KEYWORD2
 write9bit	KEYWORD2

teensy3/usb_desc.h

   #define CDC_ACM_SIZE		16
   #define CDC_RX_SIZE		64
   #define CDC_TX_SIZE		64
-  #define CDC2_STATUS_INTERFACE	2	// SerialA
+  #define CDC2_STATUS_INTERFACE	2	// SerialUSB1
   #define CDC2_DATA_INTERFACE	3
   #define CDC2_ACM_ENDPOINT	5
   #define CDC2_RX_ENDPOINT	6
   #define CDC_ACM_SIZE		16
   #define CDC_RX_SIZE		64
   #define CDC_TX_SIZE		64
-  #define CDC2_STATUS_INTERFACE	2	// SerialA
+  #define CDC2_STATUS_INTERFACE	2	// SerialUSB1
   #define CDC2_DATA_INTERFACE	3
   #define CDC2_ACM_ENDPOINT	5
   #define CDC2_RX_ENDPOINT	6
   #define CDC2_ACM_SIZE		16
   #define CDC2_RX_SIZE		64
   #define CDC2_TX_SIZE		64
-  #define CDC3_STATUS_INTERFACE	4	// SerialB
+  #define CDC3_STATUS_INTERFACE	4	// SerialUSB2
   #define CDC3_DATA_INTERFACE	5
   #define CDC3_ACM_ENDPOINT	8
   #define CDC3_RX_ENDPOINT	9

teensy3/usb_inst.cpp

 
 #ifdef CDC2_DATA_INTERFACE
 #ifdef CDC2_STATUS_INTERFACE
-usb_serial2_class SerialA;
+usb_serial2_class SerialUSB1;
 #endif
 #endif
 
 #ifdef CDC3_DATA_INTERFACE
 #ifdef CDC3_STATUS_INTERFACE
-usb_serial3_class SerialB;
+usb_serial3_class SerialUSB2;
 #endif
 #endif
 
 
 void serialEvent() __attribute__((weak));
 void serialEvent() {}
-void serialEventA() __attribute__((weak));
-void serialEventA() {}
-void serialEventB() __attribute__((weak));
-void serialEventB() {}
+void serialEventUSB1() __attribute__((weak));
+void serialEventUSB1() {}
+void serialEventUSB2() __attribute__((weak));
+void serialEventUSB2() {}

teensy3/usb_serial2.h

 	}
 
 };
-extern usb_serial2_class SerialA;
-extern void serialEventA(void);
+extern usb_serial2_class SerialUSB1;
+extern void serialEventUSB1(void);
 #endif // __cplusplus
 
 #endif // F_CPU

teensy3/usb_serial3.h

 	}
 
 };
-extern usb_serial3_class SerialB;
-extern void serialEventB(void);
+extern usb_serial3_class SerialUSB2;
+extern void serialEventUSB2(void);
 #endif // __cplusplus
 
 #endif // F_CPU

teensy3/yield.cpp

 	running = 1;
 	if (Serial.available()) serialEvent();
 #if defined(USB_DUAL_SERIAL) || defined(USB_TRIPLE_SERIAL)
-	if (SerialA.available()) serialEventA();
+	if (SerialUSB1.available()) serialEventUSB1();
 #endif
 #ifdef USB_TRIPLE_SERIAL
-	if (SerialB.available()) serialEventB();
+	if (SerialUSB2.available()) serialEventUSB2();
 #endif
 	if (Serial1.available()) serialEvent1();
 	if (Serial2.available()) serialEvent2();

teensy4/usb_desc.h

   #define CDC_TX_SIZE_480       512
   #define CDC_RX_SIZE_12        64
   #define CDC_TX_SIZE_12        64
-  #define CDC2_STATUS_INTERFACE 2       // SerialA
+  #define CDC2_STATUS_INTERFACE 2       // SerialUSB1
   #define CDC2_DATA_INTERFACE   3
   #define CDC2_ACM_ENDPOINT     4
   #define CDC2_RX_ENDPOINT      5
   #define CDC_TX_SIZE_480       512
   #define CDC_RX_SIZE_12        64
   #define CDC_TX_SIZE_12        64
-  #define CDC2_STATUS_INTERFACE 2       // SerialA
+  #define CDC2_STATUS_INTERFACE 2       // SerialUSB1
   #define CDC2_DATA_INTERFACE   3
   #define CDC2_ACM_ENDPOINT     4
   #define CDC2_RX_ENDPOINT      5
   #define CDC2_TX_ENDPOINT      5
-  #define CDC3_STATUS_INTERFACE 4       // SerialB
+  #define CDC3_STATUS_INTERFACE 4       // SerialUSB2
   #define CDC3_DATA_INTERFACE   5
   #define CDC3_ACM_ENDPOINT     6
   #define CDC3_RX_ENDPOINT      7

teensy4/usb_serial.h

         }
 
 };
-extern usb_serial2_class SerialA;
-extern void serialEventA(void);
+extern usb_serial2_class SerialUSB1;
+extern void serialEventUSB1(void);
 #endif // __cplusplus
 
 #endif // CDC2_STATUS_INTERFACE && CDC2_DATA_INTERFACE
         }
 
 };
-extern usb_serial3_class SerialB;
-extern void serialEventB(void);
+extern usb_serial3_class SerialUSB2;
+extern void serialEventUSB2(void);
 #endif // __cplusplus
 
 #endif // CDC3_STATUS_INTERFACE && CDC3_DATA_INTERFACE