EBR-1553 incorporates the advantages of legacy-1553, and accelerates the communication by 10.

It is important to identify that 1553 and CAN Bus are targeted for physical control of systems, and not for voice data or video communication.

Control communication is required to provide real-time operation, as opposed to data communication which is required to transfer large amounts of data from point A to B.

For that reason, control-communication standards need to have very compact messaging which repeats itself 50 to 100 times per second. 

As of today, 2024, for control-buses such as 1553, CAN Bus and ARINC429, EBR-1553 is the fastest protocol available for new designs.

EBR-1553 is easily scalable. The RS-485 transceivers support rates of more than 50M bps, and the solid state digital chip can be fed with higher frequencies. The required effort to support 20 Mbps and 40 Mbps EBR-1553 variants is not high, making it future proof.  

There are more than a few vendors that supply EBR-1553 test tools. These tools complement the developed node.

Some vendors have inherent limitations in the wire lengths due to poor signaling in their EBR-1553 encoder – decoder. A good EBR-1553 tester should support 40 meters (120 feet)  of cables. 

The RS-485 physical layer transceivers are built for very high frequency and easily support 10 M-bps. If the OEM assures the wires are twisted correctly, and are of the exact same length, noise immunity is maintained. 

Since the signal is ground referenced, a ground wire is needed between the BC and each RT.

As in MIL-STD-1760, EBR-1553 does not support RT-to-RT transfers.

EBR-1553 does not have redundancy, only bus A. However, a munition can support two RTs, and by that provide redundancy. 

RS-485 transceivers are not ground floating like legacy-1553 is, and thus less robust.

There is no formal RT-Validation testing in EBR-1553. This reduces the interoperability between vendors. As a result, there are two known variants of the EBR-1553 signal shape, one for Lockheed and another for Boeing. A decoder that supports both is required.  

Transformers in legacy-1553 systems are better immune to lightning than ground referenced physical layers.

There are three HUB modes in EBR-1553:

SPEC mode – RTs have an RT address, 0 to 30, and each has its port on the hub.

SWITCH mode – For a four RT system, the first RT will support RT numbers 0, 4, 8… The second supports 1, 5, 9… and so on.

LINK mode – all RTs are address 0 (!) and the BC sends all messages to RT0, but the RT number addressed depends on its port number in the hub.

From all EBR-1553 HUB modes, Link mode is the only one actually used.

Link mode implementation requires additional modifications to the legacy-1553 digital chip. There are very few companies that implement EBR-1553 BC HUB in Link mode in the digital chip, others provide work-arounds.

EBR-1553 uses the same digital part, running 10 times faster. That implies that it supports the very same features as the legacy-1553 chip, including BC, RT, MT, RT-MON, and Multiple RTs.

EBR-1553 multiplies the bit rate by 10, allowing more data transfer such as image of target transferred to smart munition after take-off.

A typical EBR-1553 implementation is composed of a digital part that can be implemented in an FPGA or ASIC, and RS-485 transceiver for the physical layer..

RS-485 transceivers are single ended as opposed to legacy-1553 transceivers which are double ended. This implies that a new decoder encoder is required in the digital portion of the EBR-1553 compared with the legacy-1553 implementation. 

No, rewiring is required. EBR-1553 requires different wires with typical impedance of 120 Ohms, as opposed to legacy 1553 wiring that is 78-Ohms.

For new systems, such as drones, and cruise missiles, EBR-1553 is highly recommended.

The bit rate is 10M-bps rather than 1M-bps in legacy MIL-STD-1553, speeds up the transfer by a factor of 10.

Using a network topology of a star between BC and Remote Terminals traditionally uses only one of the RT links, but in theory may support multiple BCs communicating with multiple RTs in parallel on all links concurrently.

For example, legacy 1553 can transfer 1 M-bps to, say, four RTs. Maximum rate would be 250 Kbps for each.

EBR-1553 can transfer 10 Mbps to those four RTs at 2.5M bps each.

4 x EBR-1553 BCs can transfer 40 Mbps in parallel, each RT is getting 10 Mbps. 

So potentially, EBR-1553 with star topology can deliver 40 x faster.

With tomorrow’s munitions, these rates are highly required.