Specifications

These connectors are manufactured and distributed by binder-USA. The series

678 connector offers a bayonet locking nut, high cycle life, and in this

configuration, five available pins. This would require the requirement of at least

four pins. The bayonet locking ability creates a more positive lock, which means

that the data and power connection will be secure. While this is not a standard

connector, it is a connector available from binder-USA’s catalog. Thus, it is not a

completely custom connector. However, it is not commonly available, and thus,

offers the advantage of a simple layer of additional security.

2.4.4 RJ-45 (Out of Spec)

Another option is to use a standard RJ-45 connector. However, given the

complexity of Ethernet networking protocol for the relatively simple uses of this

project, it is not necessary to utilize the proper protocols. These connectors could

be run “out of spec,” essentially, using them for the connector itself and not

necessary for the associated protocol.

This type of arrangement provides the best of both scenarios. Not only does it

provide a standardized connector, thus reducing costs for the manufacturer, but it

also provides security in the sense that one cannot simply interface with the unit

using a standard RJ-45 interface (for example, connecting their network-enabled

computer to either of the units). However, it will not provide physical security. Yet,

as mentioned before, it does have the advantage of easily available cables as

well. So if the user loses a cable, there is no need to purchase a proprietary

cable which would most likely be more expensive.

Nonetheless, it does fit many of the desired requirements. These connectors

offer eight pins, easily accommodating the four pins required. In addition, they

are proven as a popular networking connector. A dimensioned example of the

connector is available in Figure 2.4.4-1. They can support the high number of

duty cycles, and if the cable is equipped with a tab, also positively self-lock upon

connection, with easy connecting and disconnecting.

In addition, it would offer the possibility to more easily upgrade the design in the

future, by providing an interface that would still be used in the future. It could then

be changed to a proper Ethernet specification, such that a computer could be

more easily connected to the device in the field for data logging and

reprogramming purposes. However, as it is, this is not necessary, and this would

simply be used for the power and data lines without adhering to the Ethernet

specification.