Connector Considerations
Connectors used on the outside panels of the chassis are called panel mount type connectors, or bulk head type connectors. Any style of connector can be made into a bulk head connectors.
Connector Styles; Connectors used in multiple electric circuits should be selected to
preclude mis-mating. Where design considerations require plug and receptacles of similar
configuration in close proximity, the mating plugs and receptacles should be suitably coded or
marked to clearly indicate the mating connectors. In addition to color coding many styles of connectors may be keyed, so that only similar keyed connectors will mate together.
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This example shows a number of real panel connectors; different shell sizes, different key locations and different number of pins all designed to eliminate mismating. Also some connectors are male while others are female. Connector Mismating is not possible. |
 Keyed Circular Connectors |
Using connectors that are color coded or keyed are two ways to indicate different connector functions. Circular military connectors may be keyed in one of five different positions [copper or fiber]. Commercial D-sub connectors may be procured with different color faces. Another way to insure correct mating is to use connectors having a different amounts of contacts. For example one D-sub could be a 15-pin while another could be a 25-pin connector. Or when two 15-pin connectors are required, one connector could be a normal style D-sub while the other connector could be a High-Density D-sub which has different body dimensions.
Color Coded Connectors
Normally chassis mount connectors are the female type to protect the pins from being shorted to each other. However if two identical connectors are required than one may be male while the other female so that the cables are not mis-connected.
Connector Contacts; Unused connector contacts or contact positions for external
circuits should be provided for future use, and should be located on the periphery (outer contacts)
of the connector [provide 2 spare positions for 4 to 25 contacts, or 4 spare contacts for 26 to 100 contacts]. Additional [spare] connectors should not be used in the design.
Connector Section Recommendation; Connectors used in multiple electric circuits should be selected to preclude mismating. Where design considerations require plug and receptacles of similar
configuration in close proximity, the mating plugs and receptacles should be suitably coded or
marked to clearly indicate the mating connectors.
The use of identical connectors in adjacent locations shall be avoided. When the use of connectors of the
same shell size in adjacent locations cannot be avoided, differences in keying arrangement shall be used to prevent mismating.
Connector Selection may also need to account for EMI protection or environmental issues.
Connector EMI Protection.
Connector Vendors;
Connector Manufacturers {All types}
Military Connector Manufacturers {Metal, EMI}
D-Sub Connector Manufacturers {D Type}
Coax Connector Manufacturers, Operational Frequency Range
Telcom Connector Manufacturers {RJ style}
Industrial Ethernet Connector Manufacturers {Dust, Water Protection}
Connector Dust Caps, next page in this section.
Design Suggestion; When possible select connectors that are durable, rugged and will handle the application with out damage.
If required move the light duty connector internal to the chassis or rack and use a heavy duty connector external to the case.
Connector Selection
Fiber optic cable connector or termination end-faces shall be examined before each mate and cleaned if necessary in accordance with the cables cleaning procedures.
