= MIL-STD-1553 =
MIL-STD-1553 is a military standard published by the United States Department of Defense that defines the mechanical, electrical, and functional characteristics of a serial data bus. It was originally designed as an avionic data bus for use with military avionics, but has also become commonly used in spacecraft on-board data handling (OBDH) subsystems, both military and civil. It features multiple (commonly dual) redundant balanced line physical layers, a (differential) network interface, time division multiplexing, half-duplex command/response protocol, and can handle up to 30 Remote Terminals (devices). A version of MIL-STD-1553 using optical cabling in place of electrical is known as MIL-STD-1773.

Gateworks SBCs can use external MIL-STD-1553 cards from other vendors such as:
 * [http://www.ddc-web.com/Products/247/Default.aspx Data Device Corporation BU-67113Ux - USB]
 * [http://www.ddc-web.com/Products/245/Default.aspx Data Device Corporation BU-67114Hx - Mini-PCIe]

Note that Gateworks has not tested these cards or added the required drivers

References:
 * https://en.wikipedia.org/wiki/MIL-STD-1553