Jeff Rasmussen wrote: > Did you try removing the /dev/ttyS3 device and then re-adding it? I > also tend to use Debian's pon, poff, and pppconfig tool for modem > connections, did you try using that with Ubuntu? No to all the above, but I finally figured it out. The messages in the boot log pointed to what needed to be done: >Oct 24 02:15:34 localhost kernel: PCI: Using ACPI for IRQ routing >Oct 24 02:15:34 localhost kernel: ** PCI interrupts are no longer routed automatically. If this >Oct 24 02:15:34 localhost kernel: ** causes a device to stop working, it is probably because the >Oct 24 02:15:34 localhost kernel: ** driver failed to call pci_enable_device(). As a temporary >Oct 24 02:15:34 localhost kernel: ** workaround, the "pci=routeirq" argument restores the old >Oct 24 02:15:34 localhost kernel: ** behavior. If this argument makes the device work again, >Oct 24 02:15:34 localhost kernel: ** please email the output of "lspci" to bjorn.helgaas at hp.com >Oct 24 02:15:34 localhost kernel: ** so I can fix the driver. Here are all the steps I needed to take to get the USR 5610 56K PCI modem to work: a) install setserial. When it installs, it creates a default configuration of the serial devices. b) create the file /etc/udev/rules.d/10-local.rules, and put these lines in it: #modem KERNEL="ttyS14", SYMLINK="modem" This causes /dev/modem to be created each time the system boots. c) add pci=routeirq to the kernel boot option (in my case, in /boot/grub/menu.lst). d) reboot. These steps worked with Ubuntu Hoary. I'm confident they'll work with Ubuntu Breezy. Debian Sarge worked with just (a) and (b). Thanks for your suggestions. -Jeff P.S. Yes, I'll email Bjorn so he can fix the serial driver.