MIL-STD-1553B Data Bus Couplers

Posted in: MIL-STD-1553

Answers to a Few Frequently Asked Questions

 

At MilesTek, our core mission is to quickly and effectively meet turnkey requirements for applications that require MIL-STD-1553B compliance. We’re proud to provide the industry’s most complete line of data bus couplers, for box-style and in-line applications, along with custom harnesses and assemblies, connectors and connector termination systems, and a broad range of related accessories.

 

As with all Infinite Electronics brands, MilesTek emphasizes support and same-day shipping to meet the urgent requirements of engineers and their mission-critical products. We’re here to help.

 

In that spirit, here are some key facts about the MIL-STD-1553B serial data bus:

 

What was the development process for MIL-STD-1553?

 

As with much of our nation’s IT infrastructure, the military designed MIL-STD-1553. In the early 1970s the new standard replaced analog point-to-point wire bundles between electronic instrumentation. In 1978, leaders upgraded to version MIL-STD-1553B as a way to boost compatibility between designs by different manufacturers, as well as enhance overall flexibility. The updated standard provided explicit specifics about electrical interfaces.

 

For example, in F-16 Falcon fighter jets that first featured the standard, MIL-STD-1553B helped reliably connect and integrate onboard weapons systems with the mission computer and other applications.

 

Minus a handful of minor updates through the years, the data bus has remained the most popular and reliable militarized network for decades, used most prominently in military machines like the F-16, satellites, missiles, and the International Space Station. Commercial aircraft manufacturers utilize the technology as well, thanks to a strong, mission-critical track record of excellent EMI performance, dependability, and robustness.

 

So how does it work?

 

The MIL-STD-1553B bus features four primary elements:

 

1. The bus controller, which manages the information flow.

 

2. Remote terminals that interface one or more simple subsystems to the data bus and respond to commands from the bus controller.

 

3. The bus monitor, which is used for data bus testing.

 

4. Data bus components (data bus couplers, bus cables, terminators and connectors) that provide specific functionality.

 

The system transmits data sequentially, bit-by-bit, then receives it in a multiplexing scheme over two copper wires from computer to computer (usually at a rate of one megabit per second). Most vehicle uses for the MIL-STD-1553B employ redundant buses.

 

LAN topology typically encompasses bus couplers (coupling transformers with fault-isolation resistors), terminators and cabling via twinax cables (twisted shielded pair), and concentric twinax connectors (with a center contact and an intermediate cylindrical contact).

 

What’s the advantage of couplers?

 

Couplers play an important role in the overall system. Basically, they help reduce reflections and maintain signal impedance levels, resulting in the sort of mission-critical reliability that’s demanded from the system. Without couplers, there’d be no DC isolation or common mode rejection, and a simple shorting fault between the device’s internal isolation resistors and the main bus would lead to a failure of the entire bus.

 

Part of this function has to do with the bus coupler’s transformers, but there are also built-in fault isolation resistors designed to protect the main bus during a short circuit in the stub.

 

What does MilesTek provide?

 

At MilesTek, we offer the industry’s most complete line of MIL-STD 1553B data bus products, including:

 

1. Box-style couplers — From one-stub couplers to eight-stub couplers, and everything in between.

 

2. Inline couplers — From one-stub to four-stub inline couplers used in vehicles where light weight and small size are important.

 

3. Bus coupler kits — Integrated kits that include bus couplers, terminators, and cable assemblies.

 

Contact our digital bus experts for more information at 1 940 484 9400 or email at customerfirst@milestek.com. We offer a turnkey one-stop shop for 1553B solutions, plus cable assemblies, terminators, dust caps and other accessories. In-stock items can ship the same day.

May 11, 2021