Modern soldiers require state-of-the-art innovations, particularly when integrating connectors within advanced Wearable Soldier Systems (WSS). Key requirements for wearable soldier electronics are: increased situational awareness, increased weapons effectiveness, and increased individual agility. Connector manufacturers have worked to create connectors that offer superior sealing ratings for harsh environments where dust and debris could compromise the transfer of information in rugged telecommunications equipment. However, a single solution does not always satisfy the multitude of factors that could potentially cause equipment malfunction or threaten individual safety in the field.

The future soldier
Since 1989, when the concept of the integrated “Future Soldier” system appeared with head-mounted display and communications equipment, circular connectors have proven to be a key component of proper machine and device performance. Connectors used in modern systems are now 60% smaller and 30% lighter than older models.  Soldiers often carry gear weighing in excess of 100 kilos, so components for soldier applications need to be extremely robust yet as lightweight and small as possible. The smaller, lighter connectors enable more compact, portableend-equipment that give soldiers greater mobility and strategic positioning on the battlefield.

The advanced circular connectors are also stronger due to the combination of advanced thread-mountings and a combination of metal and copper materials that comprise the connector body. Circular connectors now satisfy the strictest environmental sealing standards, handle larger wire sizes and feature crimp-and-poke contacts – all of which are necessary on the battlefield.

Soldier safety is the top priority
Designers must consider worst-case scenarios as the standard for connector development. Dismounted connectors must still be able to function properly in the coldest and highest temperatures, and under the influence of radiation, explosive atmospheres, or when contaminated by heavy precipitation. Circular connectors used in WSS have to perform to the highest electrical requirements while affording time savings, given the potentially extreme situations where equipment must be quickly and effectively switched or engaged.   Circular connectors must retain the capacity to “rip-away” should equipment become snagged on a surface, while still being able to be reattached quickly when the soldier gets to a safer environment. Such capabilities could mean the difference between life and death in a dangerous combat situation.

Modern circular connectors usually feature a number of ways for a soldier in the field to tell whether or not the connection has been effectively made. Depending on the combat atmosphere, connectors can offer numerous confirmation options. For example, many connectors will audibly “click,” letting the soldier know that the connection is secure. However, future connector technology will enable designers to come up with other signals to indicate proper connection, as combat situations may arise where a click could clue an opposing force as to the soldier’s location. Visual confirmation is another option, and the use of low-power LEDs may be a viable alternative; though in certain situations, it may also cause a hindrance. Connector manufacturers must always consider safety the top priority for new designs.

Specifications and series
Connectors built to the standard MIL-DTL 38999 specifications are divided into different series. Series I connectors are to be used when quick disconnects and blind matings are necessary. Series I connectors must also withstand high vibrations and be suitable for use in Severe Wind and Moisture Problem (SWAMP) areas. While Series II connectors are not meant for high vibration or SWAMP areas, they still require blind mating characteristics when engaged in the field. Series III connectors are suitable for high-vibration use at elevated temperatures. Series IV connectors are to be used when quick disconnects are necessary, but they are lighter weight and therefore not meant for elevated temperatures and are not scoop-proof.

Emergency measures
As the area between advancing technology and field requirements converge, connector manufacturers must attempt to create a single connector that will satisfy a number of MIL-DTL specifications and series requirements while maintaining backwards compatibility. Circular connectors are available now that are 50% smaller than traditional MIL-STD connectors, are highly durable, and can be fully latched/engaged in a single quarter turn by hand.

Fixed, free and in-line connector variations exist to satisfy a number of connection needs, and an added benefit of multiple termination types in a single WSS assists soldiers in making the right connection on the first attempt. The amount of equipment carried by soldiers in the field includes head displays, target/firing systems, communications equipment and global positioning devices. These all require power connections and in the case of failure or manufacture, these connections may need to be shifted quickly and effectively while troops are under attack. Despite the different termination types, connector manufacturers try to create an interchangeable solution between different connections in an emergency situation.

When need becomes the standard
In order to meet EMI requirements, low shell-to-shell resistance means using a compound of different materials so there is less conflict between plug and receptacle. Receptacles must have a peripheral seal capable of one-meter immersion, and the printed circuit board receptacles must be epoxy-sealed and specially potted. An often-overlooked consideration is that of color. A connector must be matte black and the finish conductive, so damage can be quickly noticed and also to assist in camouflaging WSS gear. Black, sandblasted coating over zinc and/or nickel accomplishes this.  Any protective covering must also be black but not metallic, because the threading of metal on metal would cause too much noise – hard rubber covers finished in black oxide are necessary. A connector’s lifespan must meet or exceed at least 2,000 cycles.

The connector industry’s position today with regards to WSS will change greatly in the next few years, as has become the norm since the first appearance of WSS technology. As military operations and tactics change, so do the requirements of connector technology. New WSS prototypes include a tri-layer combat uniform.  The outer layer will be protective; the middle layer will connect power and signal devices by way of sleek, low-profile connectors; while the inner layer will provide careful monitoring of a soldier’s vital signs, drawing parallel design engineering standards between both military and medical connections. Though the tri-layer uniform is still in the planning and testing stages, connector manufacturers working to address the future design needs of military tactical technicians are assisting in multiple innovative opportunities to protect soldiers in the battlefield.