This Patch allows pyserial to find keyspan USB devices on Mac OS X
automatically.

  --md@hudora.de

--- /Users/md/Desktop/pyserial-2.0b2/serial/serialposix.py	Wed Oct  1 04:28:12 2003
+++ serial/serialposix.py	Thu Oct  9 15:16:12 2003
@@ -44,12 +44,16 @@
 elif plat[:3] == 'bsd' or  \
      plat[:6] == 'netbsd' or \
      plat[:7] == 'freebsd' or \
-     plat[:7] == 'openbsd' or \
-     plat[:6] == 'darwin':   #BSD (confirmed for freebsd4: cuaa%d)
+     plat[:7] == 'openbsd':  #BSD (confirmed for freebsd4: cuaa%d)
     def device(port):
         return '/dev/cuaa%d' % port
 
-elif plat[:4] == 'irix':     #IRIX® (not tested)
+elif  plat[:6] == 'darwin':
+    def device(port): # tested with keyspan USP-to-serial adapters
+                      # others might use /dev/tty.usbserialXX
+        return '/dev/cu.USA19QW%sP1.1' % ('1' * (port + 1))
+            
+elif plat[:4] == 'irix':     #IRIX (not tested)
     def device(port):
         return '/dev/ttyf%d' % port