Hi,
I too am puzzled about serial USB enumeration.
I have just got around to trying a RFXCOM 433Mhz receiver for X10 and various sensors.
When I plugged it into the Sheevaplug USB type A socket, the kernel ( bog standard from Installer v1.0 V 2.6.30.2 ) showed this:-
usb 1-1: new full speed USB device using orion-ehci and address 3
usb 1-1: configuration #1 chosen from 1 choice
ftdi_sio 1-1:1.0: FTDI USB Serial Device converter detected
usb 1-1: Detected FT232RL
usb 1-1: FTDI USB Serial Device converter now attached to ttyUSB0
root@ubuntu:/var/log#
Now the funny thing is that I am already using /dev/ttyUSB0 to connect to the Sheevaplug with PUTTY, looking at /dev
root@ubuntu:/var/log# dir /dev
block null ram4 tty24 tty53 ttype
bus port ram5 tty25 tty54 ttypf
char ppp ram6 tty26 tty55 ubi0
console psaux ram7 tty27 tty56 ubi0_0
core ptmx ram8 tty28 tty57 ubi_ctrl
cpu_dma_latency pts ram9 tty29 tty58 urandom
fd ptyp0 random tty3 tty59 usbdev1.1
full ptyp1 rtc0 tty30 tty6 usbdev1.1_ep00
initctl ptyp2 serial tty31 tty60 usbdev1.1_ep81
input ptyp3 shm tty32 tty61 usbdev1.3
kmem ptyp4 sndstat tty33 tty62 usbdev1.3_ep00
kmsg ptyp5 stderr tty34 tty63 usbdev1.3_ep02
log ptyp6 stdin tty35 tty7 usbdev1.3_ep81
loop0 ptyp7 stdout tty36 tty8 vcs
loop1 ptyp8 tty tty37 tty9 vcs2
loop2 ptyp9 tty0 tty38 ttyS0 vcs3
loop3 ptypa tty1 tty39 ttyS1 vcs4
loop4 ptypb tty10 tty4 ttyUSB0 vcs5
loop5 ptypc tty11 tty40 ttyp0 vcs6
loop6 ptypd tty12 tty41 ttyp1 vcsa
loop7 ptype tty13 tty42 ttyp2 vcsa2
mapper ptypf tty14 tty43 ttyp3 vcsa3
mem ram0 tty15 tty44 ttyp4 vcsa4
mtd0 ram1 tty16 tty45 ttyp5 vcsa5
mtd0ro ram10 tty17 tty46 ttyp6 vcsa6
mtd1 ram11 tty18 tty47 ttyp7 xconsole
mtd1ro ram12 tty19 tty48 ttyp8 zero
mtdblock0 ram13 tty2 tty49 ttyp9
mtdblock1 ram14 tty20 tty5 ttypa
net ram15 tty21 tty50 ttypb
network_latency ram2 tty22 tty51 ttypc
network_throughput ram3 tty23 tty52 ttypd
root@ubuntu:/var/log#
You can see that there is only one ttyUSB.
So my question is how do I set up udev rules ( I suppose ) to enumerate a ttyUSB for the RFXCOM receiver.
I tried another experiment, I disconnected my min usb cable and the PUTTY terminal, and used SSH to look at what was going on when I plugged my RFXCOM receiver in to the type A port.
What happened was that the kernel "found " the ftdi device, and connected it to ttyUSB0 again!. However although the receiver was supposed to be pumping out loads of ascii text, there was nothing from /dev/ttyUSB0. When I reconnected the PUTTY cable to the min slot and used ttyUSB0, it picked up where it left off, connected as a Linux console! So I assume that the data structure for ttyUSB0 originally set up on first connection of the PUTTY cable to the "jtag" port has persisted through the disconnection
Advice gratefully received
cheers
Patrick