import serial
import os

def scan():
    """
    gibt eine Liste von Strings der Namen der verfügbaren Ports zurück
    """
    L = []
    for i in range(10):
        try:
            s = serial.Serial('/dev/ttyS'+str(i))
            L.append(s.portstr)
            s.close()   
        except serial.SerialException:
            pass
    for i in range(10):
        try:
            s = serial.Serial('/dev/ttyUSB'+str(i))
            L.append(s.portstr)
            s.close()   
        except serial.SerialException:
            pass
    for i in range(10):
        try:
            s = serial.Serial('COM'+str(i))
            L.append(s.portstr)
            s.close()   
        except serial.SerialException:
            pass
     # Neuer Code für Mac OS X
    if os.uname()[0] == 'Darwin':
        try:
            s = serial.Serial('/dev/tty.usbserial')
            L.append(s.portstr)
            s.close()
        except serial.SerialException:
            pass
        for i in range(20):
            try:
                s = serial.Serial('/dev/tty.usbserial'+str(i))
                L.append(s.portstr)
                s.close()
            except serial.SerialException:
                pass
    return L

import tkinter as tk

class View(tk.Tk):
    def __init__(self):
        tk.Tk.__init__(self)
        # Fenster
        self.title("serielle Schnittstellen")
        self.geometry('260x80+400+100')
        self.protocol("WM_DELETE_WINDOW",self.Halt)
        # Optionmenu
        L = scan() 
        self.vS = tk.StringVar(master=self)
        self.vS.set(L[0])
        self.oS = tk.OptionMenu(self,self.vS,*L, command=self.cbOption)
        self.oS.place(x=20,y=20,width=150)

    def cbOption(self,wert):
        print(wert)

    def Halt(self):                  
        v.quit()                             
        v.destroy()

v = View()

                 

v.mainloop()