iBook2 500Mhz/66Mhz: Well, I loaded up benh's newest kernel source and Raoul kindly sent me a ready-made config file. It seems to be a hardware modem after all, as the new test script from connexant doesnt find anything.
dmesg | grep 8530 PowerMac Z8530 serial driver version 2.0 tty00 at 0xd980f020 (irq = 22) is a Z8530 ESCC tty01 at 0xd9816000 (irq = 23) is a Z8530 ESCC setserial -a /dev/ttyS0 /dev/ttyS0, Line 0, UART: unknown, Port: 0xd980f020, IRQ: 22 Baud_base: 0, close_delay: 50, divisor: 16 closing_wait: 3000 Flags: spd_normal setserial -a /dev/ttyS1 /dev/ttyS1, Line 1, UART: unknown, Port: 0xd9816000, IRQ: 23 Baud_base: 0, close_delay: 50, divisor: 16 closing_wait: 3000 Flags: spd_normal HOWEVER: pppconfig still doesn't find a modem, neither does kppp or wvdialconf. But I don't have any reason to believe the kernel is to blame for that.