No, you can't plug in a USB Fax machine to an obi, and receive faxes
similar to you can't plug a USB Fax machine into your automobile USB port, and receive faxes
It was not made for that function
"The OBi202 USB port serves multiple purposes. Using the OBiWiFi Wireless Adapter, the OBi202
can be placed anywhere within range of an 802.11b/g/n access point. Or, the USB port can be connected to a storage device to enable local and remote access of stored files over the Internet by authorized users."
also USB 2.0 for use with OBiWiFi, OBiBT, OBiLINE