Add the cy device to your kernel configuration (note that your irq and iomem settings may differ).

device cy0 at isa? irq 10 iomem 0xd4000 iosiz 0x2000

Rebuild and install the new kernel.

Make the device nodes by typing (the following example assumes an 8-port board)^[1]:

# cd /dev
# for i in 0 1 2 3 4 5 6 7;do ./MAKEDEV cuac$i ttyc$i;done

If appropriate, add dialup entries to /etc/ttys by duplicating serial device (ttyd) entries and using ttyc in place of ttyd. For example:

ttyc0   "/usr/libexec/getty std.38400"  unknown on insecure
ttyc1   "/usr/libexec/getty std.38400"  unknown on insecure
ttyc2   "/usr/libexec/getty std.38400"  unknown on insecure
…
ttyc7   "/usr/libexec/getty std.38400"  unknown on insecure

Reboot with the new kernel.