if someone else is looking for the UART pin layout of the omninas kd20 or kd21 the screenshots can now be found here (since they are not available any more under the previouse url provided by @Peacemaker)
* https://gitorious.org/openwrt-oxnas/openwrt-oxnas-gitorious-wiki.git/?p=openwrt-oxnas:openwrt-oxnas-gitorious-wiki.git;a=tree
serial port layout:
* https://gitorious.org/openwrt-oxnas/openwrt-oxnas-gitorious-wiki.git/?p=openwrt-oxnas:openwrt-oxnas-gitorious-wiki.git;a=blob;f=omninas-kd20-serial.jpg;h=cf338336a5e617b3da6930f442871d53212446a2;hb=HEAD
* https://gitorious.org/openwrt-oxnas/openwrt-oxnas-gitorious-wiki.git/?p=openwrt-oxnas:openwrt-oxnas-gitorious-wiki.git;a=tree
serial port layout:
* https://gitorious.org/openwrt-oxnas/openwrt-oxnas-gitorious-wiki.git/?p=openwrt-oxnas:openwrt-oxnas-gitorious-wiki.git;a=blob;f=omninas-kd20-serial.jpg;h=cf338336a5e617b3da6930f442871d53212446a2;hb=HEAD