creating ttyS5?

[Lance Hoffmeyer <lanceh@ibm.net>]

I just purchased a pci-modem from Actiontec that uses a Lucent chip and 
on the box it says it is compatible with Linux.  I have to create a 
ttyS4 (com 5)

I have done a /dev/MAKEDEV ttyS4 and this appears to create the file.

I then try to setserial /dev/ttyS4 uart 16550A port 0xd800 irq 5
but I get "device ttyS4 not found"?

How do I create ttyS4?  Here is the info when I cat /proc/pci




  Bus  0, device   9, function  0:
    Communication controller: Lucent (ex-AT&T) Microelectronics 
                   Unknown device (rev 0).
      Vendor id=11c1. Device id=480.
      Medium devsel.  Fast back-to-back capable.  IRQ 5.  Master Capable.  
      No bursts.  Min Gnt=252.Max Lat=14.
      Non-prefetchable 32 bit memory at 0xef001000 [0xef001000].
      I/O at 0xd800 [0xd801].
      I/O at 0xdc00 [0xdc01].
      I/O at 0xe000 [0xe001].