Frequently Asked Questions

MTL-DTL-38999 Circular Connector FAQs


What applications are MIL-DTL-38999 connectors used for?

MIL-DTL-38999 connectors are widely used in:

  • Military and defense systems such as ground vehicles, shipboard systems, avionics, radar, and C4ISR systems 
  • Aerospace applications such as aircraft, satellites, and space exploration
  • Commercial air applications
Can I request custom configurations for MIL-DTL-38999 connectors?

Absolutely! Amphenol Aerospace offers customizable solutions to meet your specific requirements, including unique shell sizes, contact arrangements, and plating options.

Where can I purchase Amphenol Aerospace MIL-DTL-38999 connectors?

You can purchase our connectors through our global network of distributors or by contacting our expert team of product managers and specialists. 

Are there any resources available for MIL-DTL-38999 connectors?

Yes, we provide datasheets, catalogs, and technical drawings on our website. Visit our MIL-DTL-38999 Connectors page and our product literature page for more information.

Can MIL-DTL-38999 connectors be used in space applications?

Yes, MIL-DTL-38999 connectors may be used in space applications when properly configured and qualified to meet program-specific requirements. Material selection, plating, and testing must align with the environmental conditions of the intended mission, including vacuum, radiation exposure, and temperature extremes.

What are the temperature ratings for Amphenol Aerospace MIL-DTL-38999 connectors?

Our MIL-DTL-38999 connectors are rated for operation in temperatures typically ranging from -65 °C (-85 °F)  to +175 °C (347 °F), depending on the specific configuration. Specialty connectors such as our Deep Space 38999 have been temperature cycled in temperatures as low as -195 °C (-319 °F). 

Do you offer MIL-DTL-38999 connectors with gold-plated contacts?

Yes, gold-plated contacts are available for enhanced conductivity and corrosion resistance.

How do I identify the correct MIL-DTL-38999 connector for my application?

Our team can help you select the right MIL-DTL-38999 connector based on your specific requirements, including size, contact arrangement, and environmental conditions. 

Connector selection is based on a variety of factors, including:

  • Shell size and insert arrangement
  • Contact type and termination method
  • Environmental and temperature requirements
  • Mounting style and keying requirements

We provide catalogs, drawings, and a part configurator to help you find the right connector for your application. 

You can also select a technology category on our website or contact our customer service team for assistance.

Do Amphenol Aerospace D38999 circular connectors come with a warranty?

Yes, our interconnect products come with a warranty. Details can be found on our website or by contacting customer service.

MTL-DTL-38999 Series I LJT Connector FAQs

What are the key features of Amphenol Aerospace MIL-DTL-38999 Series I LJT connectors?
  • 3-Point Bayonet Coupling: Provides quick, positive mating with tactile and visual confirmation.
  • Lightweight, Space-Saving Design: Optimized for aerospace and defense applications.
  • Scoop-Proof Contact Protection: Prevents bent pins and short circuits during mating (LJT specific).
  • 5-Key/Keyway Polarization: Eliminates mismating and provides alternate keying positions.
  • Environmental Sealing: Fluorinated silicone interfacial seal and main joint gasket for moisture resistance.
  • Broad contact options: Including crimp, solder, PCB, wire wrap, coax, twinax, triax, fiber optic, and thermocouple configurations.
  • Hermetic options: Available with leakage rates down to 1 × 10⁻⁷ cm³/sec helium.
Are MIL-DTL-38999 Series I LJT connectors customizable?

Yes, Amphenol Aerospace offers a wide range of customization options, including:

  • Multiple shell styles (wall mount, jam nut, box mount, straight plug, 90° plug)
  • Shell sizes and insert arrangements
  • Crimp, solder, PCB, and specialty contact types
  • Standard cadmium-over-nickel plating and optional finishes
  • High-temperature (LJTS), chemical-resistant (LJTN), and breakaway lanyard-release versions
What is the temperature range for Amphenol Aerospace MIL-DTL-38999 Series I connectors?

MIL-DTL-38999 Series I connectors are designed to operate in extreme temperatures, typically ranging from -65 °C (-85 °F)  to +175 °C (347 °F), depending on the configuration.

Can I use MIL-DTL-38999 Series I connectors in underwater applications?

Series I LJT connectors provide environmental sealing against moisture and contaminants when properly mated. For continuous underwater or pressure-rated applications, hermetic connectors or application-specific sealing solutions should be evaluated.

Do Series I LJT connectors support breakaway functionality?

Yes. LJT breakaway (lanyard-release) plugs are available and provide fail-safe, quick-disconnect functionality while remaining fully intermateable with standard LJT receptacles.

How do I ensure proper installation of MIL-DTL-38999 Series I connectors?

Amphenol Aerospace provides detailed installation guides and technical support to ensure proper installation and performance.

MTL-DTL-38999 Series II JT Connector FAQs

What are the key features of Amphenol Aerospace MIL-DTL-38999 Series II JT connectors?
  • Bayonet Coupling: Quick and secure mating for high-vibration environments.
  • High Performance: Provides dependable power and signal connectivity 
  • Durability: Operates from −65 °C (-85 °F) to +175 °C (347 °F) and withstands shock and vibration.
  • Customizable: Available in various shell sizes, contact arrangements, and plating options.
  • Environmental Sealing: Provides excellent protection against moisture, dust, and other contaminants.
Are MTL-DTL-38999 Series II connectors customizable?

Yes, Amphenol Aerospace offers a wide range of customization options, including shell sizes, contact arrangements, plating materials, and environmental sealing options.

What is the temperature range for Amphenol Aerospace MIL-DTL-38999 Series II JT connectors?

These connectors are designed to operate in temperatures ranging from -65 °C (-85 °F)  to +175 °C (347 °F), depending on the configuration.

How do I identify the right D38999 Series II JT connector for my application?

Visit our part configurator or contact our customer service team for assistance.

What plating options are available for these MIL-DTL-38999 Series II JT connectors?

Plating options include olive drab cadmium, electroless nickel, black zinc-nickel, Durmalon, AP-93, and other corrosion-resistant finishes depending on application requirements.

Are D38999 Series II JT connectors suitable for space applications?

Series II JT connectors may be used in space applications when properly configured and qualified to meet program-specific requirements.

How much do D38999 Series II connectors weigh? 
The weight varies depending on the shell size and configuration. Please refer to Amphenol Aerospace's D38999 catalog for detailed specifications.

MTL-DTL-38999 Series III TV Connector FAQs

What are the key features of MIL-DTL-38999 Series III TV connectors?

MIL-DTL-38999 Series III TV connectors are designed for high-vibration, harsh-environment aerospace and defense applications and feature:

  • Triple-start threaded coupling system for secure mating and resistance to vibration and shock
  • High-density contact arrangements, supporting up to 128 contacts depending on shell size and insert arrangement
  • EMI shielding is achieved through metal-to-metal coupling and optional 360-degree grounding fingers.
  • Environmental sealing for protection against moisture, dust, and sand when properly mated
  • Corrosion-resistant finish options, including cadmium over nickel, electroless nickel, stainless steel, zinc-nickel, and others (finish dependent)
  • Scoop-proof contact design to help minimize contact damage during mating
What applications are MIL-DTL-38999 Series III connectors suitable for?

Series III connectors are commonly used in applications requiring high reliability under severe mechanical and environmental conditions, including:

  • Military and commercial aircraft (avionics, radar, and communications systems)
  • Ground vehicles and armored systems
  • Naval and shipboard electronics
  • Missiles, weapons systems, and stores-management equipment
  • Aerospace and defense platforms subject to high vibration and temperature extremes
What is the operating temperature range of MIL-DTL-38999 Series III connectors?

Standard MIL-DTL-38999 Series III connectors are rated for operation from −65 °C (−85 °F) to +175 °C (347 °F).

Select high-temperature configurations may support operation up to +200 °C (392 °F) when specifically designed and qualified for elevated-temperature applications.

Lower temperature limits and full operating ranges depend on shell material, finish, insert material, and service class. For exact limits, refer to the applicable finish and service-class tables in the catalog.

Are MIL-DTL-38999 Series III connectors resistant to corrosion?

Yes. Series III connectors are available with multiple corrosion-resistant finishes, including:

  • Cadmium over nickel
  • Electroless nickel
  • Passivated stainless steel
  • Zinc-nickel and other RoHS-compliant alternatives

Salt-spray performance is finish-dependent and ranges from 48 hours (electroless nickel) to 500 hours and up to 2000 hours (dynamic), depending on finish and material selection. Refer to Amphenol Aerospace's MIL-DTL-38999 catalog finish table for specific performance values.

What types of contacts are available for Series III connectors?

MIL-DTL-38999 Series III connectors support a wide range of contact technologies, including:

  • Crimp contacts
  • PCB / PC-tail contacts
  • Coaxial and twinax contacts
  • Fiber-optic termini

Additional contact styles may be available depending on the insert arrangement and configuration. Please refer to the MTL-DTL-38999 catalog or contact Amphenol Aerospace for application-specific options.

What is the EMI shielding performance of MIL-DTL-38999 Series III connectors?

Series III connectors provide up to 65 dB attenuation at 10 GHz in qualified configurations.

This performance is achieved through metal-to-metal coupling and 360-degree grounding fingers.

Actual shielding effectiveness is configuration- and finish-dependent.

What shell sizes and configurations are available?

Shell sizes include:

  • Standard sizes: 9, 11, 13, 15, 17, 19, 21, 23, 25
  • XL38999 sizes: 25L, 33, 37 (special insert arrangements)

Shell styles include:

  • Wall-mount receptacles
  • Box-mount receptacles
  • Jam-nut receptacles
  • Straight plugs
  • Hermetic solder-mount or weld-mount receptacles

Custom configurations are available; consult Amphenol Aerospace for details.

Are RoHS-compliant options available for Series III connectors?

Yes. RoHS-compliant Series III connector options are available.

Availability depends on finish, material, and configuration. Contact Amphenol Aerospace for RoHS-compliant part number options.

What accessories are available for MIL-DTL-38999 Series III connectors?

A broad range of accessories is available, including:

  • Backshells and adapters
  • Protection and dust caps
  • Sealing accessories
  • EMI grounding and shielding accessories

Accessory availability varies by shell style and configuration.

What tools are required for contact insertion and extraction?
  • Insertion: Plastic or metal insertion tools appropriate to the contact size
  • Extraction: Plastic or metal extraction tools designed to remove contacts without damaging the connector

Amphenol Aerospace-recommended application tools should be used.

Can MIL-DTL-38999 Series III connectors be used in space applications?

Yes. Certain Series III connectors are available in Class G low-outgassing configurations, suitable for vacuum and space applications. Availability is configuration-specific and should be confirmed during part selection.

What is the durability of MIL-DTL-38999 Series III connectors?

Durability depends on configuration, materials, and finish.
Series III connectors are evaluated through mechanical endurance and environmental testing as part of MIL-DTL-38999 qualification. Refer to the applicable specification or test documentation for exact mating-cycle limits.

How do I select the right Series III connector for my application?

Connector selection is based on:

  • Required number of contacts and insert arrangement
  • Shell size and shell style (wall mount, jam nut, straight plug, etc.)
  • Environmental conditions (temperature, vibration, corrosion exposure)
  • Contact type and termination method

We provide catalogs, drawings, and a part configurator to help you find the right connector for your application. 

You can also select a technology category on our website or contact our customer service team for assistance.

 

High Speed Connector FAQs

 
Can Amphenol Aerospace provide custom high-speed connector solutions?

Absolutely. Our engineering teams work closely with customers to develop custom solutions tailored to your specific needs, from design and prototyping to final production.

 

What is the Centaur Series, and what separates it from other high-speed interconnects?

The Centaur Series is a high-speed, high-density ruggedized cable assembly system housed in MIL-DTL-38999 Series III size 17, 23, and 25 shells. Centaur supports up to 12, 32, or 40 100Ω differential pairs depending on shell size and is designed for high-bandwidth applications up to 10 Gbps PAM4.

 

Available in circular cable assemblies, PCB solder-tail, and compliant eye press-fit configurations, Centaur is engineered for rugged environments with VITA 47 shock and vibration performance and optional IP67 sealing.

 

For space applications, the Centaur Sagittarius variant offers low-outgassing materials, electroless nickel plating, and supports data rates up to 56 Gbps PAM4.

 

How do your connectors ensure signal integrity in high-noise environments?

Our connectors feature:

 

  • Differential signaling for enhanced noise immunity.
  • Crosstalk reduction to minimize interference.
  • High-frequency operation to meet increasing bandwidth demands.
  • Matched impedance differential pairs (100 or 150 Ohm depending on contact type)
What is the difference between standard and rugged high-speed connectors?

Standard connectors are designed for general-purpose use, while rugged high-speed connectors are built to withstand harsh environments, including extreme temperatures, vibration, and shock. They are essential for military, space, and commercial aviation applications.

 

How do high-speed connectors support modern aerospace systems?

High-speed connectors enable the rapid transmission of large volumes of data, which is critical for modern aerospace systems like avionics, radar, and communication systems. They ensure reliable performance in high-bandwidth applications.

 

Can high-speed connectors be used in space applications?

Select high-speed connector configurations are available in Space Grade or vacuum-degassed versions. Availability is configuration-specific and should be confirmed during part selection.

 

How do I choose the right high-speed connector for my application?

Selecting the appropriate high-speed connector depends on several key factors:

 

  • Data rate and protocol requirements (e.g., Ethernet, USB, HDMI, Fibre Channel)
  • Impedance requirements (50, 75, 100, or 150 Ohm depending on contact type)
  • Contact technology (Quadrax, Differential Twinax, Octonet, Coax, FiberQuad)
  • Environmental conditions (temperature range, vibration, corrosion exposure)
  • Connector style and packaging constraints (circular MIL-DTL-38999, rectangular, PCB-tail, or cable assembly)

Amphenol Aerospace provides catalogs, performance data, and customer support to assist you with proper contact and connector selection for your unique application needs. Visit our High Speed Products Catalog and Centaur Catalog for more information. 

 

Do you offer cable assemblies for high-speed connectors?

Yes, Amphenol Military High Speed has the design and manufacturing expertise to design a complete end-to-end cable assembly solution for your application.

Class L MIL-DTL-22992 Connector FAQs

 
What current ratings and wire sizes do Amphenol Class L Connectors support?

Amphenol Class L connectors support:

 

  •  Current: 40A to 200A continuous
  •  Wire sizes: 6 AWG to 4/0 AWG
How does the arc-quenching design work in Class L Connectors?

Recessed socket contacts within the insert create an arc-suppressing chamber that protects the user when connectors are separated under load.

 

What makes Class L connectors waterproof in both mated and unmated conditions?

A unique combination of grommets and seals provides waterproofing in any condition, mated or unmated, capped or uncapped.

 

Can Class L Connectors be repaired in the field?

Yes, they feature:

 

  •  Field-serviceable contacts (crimp-type)
  •  Replaceable seals and grommets
  •  Individual replacement components for common wear parts
What accessories are typically included with Class L Connectors?

Available accessories include protective caps, sealing glands, and strain relief components. Specific accessories supplied depend on the connector type and configuration. Visit Amphenol Aerospace's MIL-DTL-22992 Class L catalog for more information.