MIL-DTL-38999 - Series I LJT - Series II JT

Amphenol® LJT and JT Series subminiature cylindrical  connectors are qualified to MIL-DTL-38999*, Series I and II respectively. These connectors were developed to meet the needs of the aerospace industry, and  provided the impetus for development of the  MIL-C-38999 specifications, which has been  superseded by MIL-DTL-38999. Meeting or exceeding  MIL-DTL-38999 requirements,

Amphenol® JT/LJT  connectors feature:
MIL-DTL-38999, Series II JT MIL-DTL-38999, Series I LJT 
Components Shell components are impact extruded or machined bar stock  aluminum. Standard plating on shell com ponents is cadmium over  nickel. Many finishes are optional . Hermetic seal receptacles are available in carbon steel or stainless steel shells. Dependable 5 key/keyway polarization with bayonet lock coupling is incorpo rated to aid and assure positive mating.
Insert material is a rigid dielectric with excellent electrical character- istics, providing durable protec tion for molded-in solder type contacts. Contrasting letter or number designations are used on insert faces.
A fluorinated silicone interfacial seal wafer is fea tured on the mating face of “crimp type pin” inserts. This assures complete electrical  isolation of pins when connector halves are mated. In addition, a main joint gasket is installed in the receptacle for moisture sealing between connector halves. Both features are also available for hermetic  receptacles.
Contacts Maximum design flexibility is built into the JT/LJT Series, with a mini- mum of 2 to a maximum of 128 circuits per connector in a wide variety of contact arrangements. Contacts are available in sizes 8, 10, 12, 16, 20, 22, 22D and 22M with standard 50 micro inch minimum gold plating (100 micro inches optional). All socket contacts are probe proof. Crimp type rear removable contacts are featured in JT-R and LJT-R  connectors. Solder termination contacts are also available, as well as PCB, wire wrap, thermocouple, fiber optic, coaxial, triaxial and twinax  contact options.
Optional Features High temperature capability of 392°F is available only in JTS or LJTS crimp type connectors. High temperature versions feature gold plated contacts, high temperature shell plating, stainless steel cou pling nut spring, and epoxy inserts/fluorinated sili cone grommet combination. Standard temperature capability for both solder and crimp is 302°F.
The JTN or LJTN type connectors are available for N2O4resistance provided they are mated, and un-grommeted rear faces are  suitably protected. For complete listing and definition of connector types, shell styles and service classes, see How to Order, pages 62 & 63. 

Features & Benefits

• Lightweight, Space Saving Design
• Contact Protection - 100% scoop-proof LJT design prevents   bent pins and short circuits dur ing mating
• Quick Positive Coupling - 3 point bayonet lock system • Mismating Eliminated - with 5 key/keyway design
• Error Proof Alternate Positioning - insured by different key/  keyway locations
• EMI Shielding - grounding fingers standard in LJT Series;   optional in JT Series
• Nine Shell Sizes and a Variety of Shell Styles
• Contact Options - size 8, 10, 12, 16, 20, 22M and 22D Crimp,   Solder, PCB, Wire wrap, Coax, Twinax, Triax, Thermocouple,   Fiber Optic and Fil ter
• Fixed Solder Contacts - Amphenol MIL-DTL-38999 Series I   LJT and II JT, are available in solder versions as both   Commercial and Military qualified to MIL-DTL-27599 
• Hermetic - air leakage limited to 1 X 10-7 cm3 per second   optional
• “Breakaway” Lanyard Release Style - available in LJT plugs.   Provides quick disconnect of the connector plug and receptacle   with axial pull on the lanyard. 
• Inventory Support Commonality - uses stan dard   MIL-DTL-38999 contacts, insert arrangements and   application tools.
• RoHS Compliant Product Available

SJT - Scoop Proof LJT

Amphenol® SJT connectors combine unique design fea tures of the  scoop-proof LJT series within standard mount ing dimensions of JT types. Available in a wide range of shell sizes, finishes, insert arrangements  and accessories.
Components Standard connectors use aluminum shells.  Standard plating on shell components is cadmium over nickel with many optional finishes available.  A dependable 5-key/keyway shell polarization with bayonet-lock coupling is incorporated to aid and assure positive mating.
The insert material is a high-temperature, rigid dielectric polymer providing excellent electrical characteristics. A fluorinated silicone interfacial seal is featured on the mating face of the pin inserts, assuring complete electrical isolation of the pins when connector halves are mated.  Contrasting letter or number designations are used on the insert faces.  A main joint gasket is installed in the receptacles  for moisture sealing between connector halves.
Serrated and threaded shells, with a moisture sealing pilot for back shells, accept a wide  range of accessories.
Hermetic seal receptacles are available in carbon steel or stainless steel shells.  Contacts Rear insertable/rear release crimp contacts are standard in SJT connectors.  Power contacts  are available in sizes 10, 12, 16, 20, 22M and 22D.  All socket contacts are probe proof.   Standard contact plating is 50 mµ minimum gold. Coaxial contacts are available in sizes 8, 12  and 16 to accommodate a wide range of coaxial cables; see Coaxial contact information in the  High Speed Contact section of this catalog.  Size 8 and 12 Twinax contacts are also available; see  Concentric Twinax contact information in the High Speed Contact section of this catalog.
Optional Features Special adaptations of the SJT are available for hermetic and high temperature applications. The SJTS high temperature con nector is rated at 392°F. SJT hermetic receptacles are described on page 104.
Specials Special types are available, such as connectors less contacts and circular rack and panel connectors with solderless wrap contacts. A complete listing of connector types, shell styles and service classes appears on page 99, How to Order.  For further informa tion on special application requirements.

*MIL-DTL-38999 Series I supersedes MIL-C-38999 Series I.
**MIL-DTL-38999 Series III supersedes MIL-C-38999 Series III.


MIL-DTL-38999 - Series III - TV

Amphenol ®  Tri-Start MIL-DTL-38999* Series III Connectors offer the highest performance capabilities for both general duty and severe environment applications. Meeting or exceeding MIL-DTL-38999 Series III require ments, the Tri-Start connector with standard metal shells (aluminum or stainless steel with several finish options)  offers these features:
• EMI Shielding - solid metal-to-metal coupling, grounding fingers,  electroless nickel plating, and thicker wall sec tions provide superior EMI shielding capability of 65dB minimum at 10 GHz
• Contact Protection - recessed pins in this 100% scoop-proof  connector minimize potential contact damage
• Moisture Resistance - improved interfacial seal design helps prevent electrolytic erosion of contacts
• Corrosion Resistance - shells of stainless steel or cad mium over nickel plating withstand a 500 hour salt spray exposure
• Vibration/Shock - operates under severe high tempera ture  vibration, through 200°C
• Firewall Capability - available in a stainless steel shell,  class RK, RS
• Lockwiring Eliminated - unique, self-locking, quick cou pling  connector eliminates lockwiring
• Quick Coupling - completely mates and self-locks in a 360° turn  of the coupling nut
• Inventory Support Commonality - uses standard MIL-DTL-38999 contacts, application tools, insert arrangements
• Electrostatic Discharge Protection (ESD) - protection for  sensitive circuitry without diodes, varistors, etc., with the use of the Faraday Cage principle which shunts high voltage, high current  discharge events (see page 331)
• Hermetic- air leakage limited to 1 X 10-7 cm3 per second optional
• Qualified Specifications - Stainless Steel qualified to BACC63DB and BACC63DC specifications
• Deep Reach Shells - For increased panel thickness
• Stand-off Flange Shells - For attachments to Printed   Circuit Boards.
• Connector with Integral Strain Reliefs




MIL-DTL-38999 - Series III Cable Clamps












MIL-DTL-38999 - Series III Protection Caps












38999 PCB

Amphenol provides circular connectors with PC Tail contacts. This catalog section features the 38999 Series III, II, and I connectors which are ideal for printed circuit board applications, either with rigid attachment or with flex print assembly attachment. For information on other Amphenol circular connectors with PC Tail contacts, consult Amphenol, Sidney NY.
• Lightweight, compact, high density and high reliability cylindrical
• Operating voltage to 900 VAC (RMS) at sea level
• Environmentally resistant
• Solder or crimp rear release contacts in mating plug
• Series I (LJT) - Bayonet coupling
• Scoop-proof (recessed pins) offers maximum contact protection
• Series II (JT) - Bayonet coupling
• For applications requiring maximum weight/space savings and reliability
• Series III (Tri-Start) - Threaded, quick coupling in one complete turn
• Designed for general duty as well as severe       environmental applications
• Superior EMI shielding with grounding fingers and      metal-to-metal mating
• Filter/Transient protection versions available
• Scoop-proof contact protection
• Stainless steel firewall versions, and composite versions
• Available in Hermetics


Power 38999

KVTV 38999

The KVTV connector series is a collaboration of the MIL-DTL-38999 and MIL-DTL-5015 technologies designed to push high amperage / voltage in harsh environments. The KVTV was originally driven by the need for military vehicles to power more systems while reducing their  dependency on diesel fuels. Many of our commercial and hybrid 5015 connectors are no longer seen as viable solutions due to their design limitations for these applications. This newly designed connector  series offers you the environmental and vibration standards of the  MIL-DTL-38999 while utilizing the readily available 5015 inserts and  rear accessories.
Amphenol Power Solutions Series KVTV
Features / Benefits Mil-DTL-38999 Series III Shells and Outer Coupling
• Providing Shell to shell bottoming and EMI banding for EMI/RFI protection.
• Environmental sealing which will meet the 38999 requirements for humidity   and submersion testing.
• Will meet shock and vibration requirements of 38999
• Shell sizes 25 and larger allowing more options to carry higher power for     your applications.
• Will come standard with over molded coupling nuts providing extra   durability and grip.
MIL-DTL-5015 Series Inserts and Backshell Accessories
• Will be available in familiar 5015 patterns as well as some new patterns allowing   for higher amperage / voltage requirements. (See Contact Arrangement Chart)
• Will come standard with a Silicone based insert material for higher CTI and service class,   but will also be available with High Temperature Flouroelastomer or Neoprene giving some   versatility in your applications while providing an operating temperatures rating from   -65C up to 200C.
• Available with standard 5015 style back shells and rear accessories giving the extra sealing    and support needed in a harsh environment.
Customizable to Meet Your Needs
• Multiple contact styles and terminations will come standard in Crimp with available options for    Solder, Pencil Clip, Internal Threaded, Tabbed with through hole, PCB and our   RADSOK® technology.
Multiple Finishes
• Will be standard OD cadmium with available options including Durmalon,   our Military qualified alternative to Cadmium



Mil-DTL-38999 Series III circular connectors with hyperbolic contacts that extend the boundaries of high power connector technology.  Designed to meet the latest military and industrial specifi cations, Rhino 38999 connectors also meet stringent safety requirements. As one of the foremost manufacturers of both connectors and interconnect systems specifi cally for applications within military, aerospace and industrial markets, Amphenol has recognised a distinct trend towards increased power and voltage requirements within such applications as military and electric drive vehicles, aircraft and intelligence bases stations. The use of RADSOK contacts creates an electrical interface that exceeds typical interconnect requirements via a hyperbolic socket contact construction which distributes normal forces over a high percentage of the mating surface to ensure a smooth and even engagement force with exceptionally high performance under vibration. The large surface area of the socket contact also results in a very low contact resistance enabling much higher current ratings compared to other power contact designs. High reliability applications including vehicular, aerospace, industrial, automation, mining, offshore and other harsh environments can all be addressed using the Rhino 38999 Series.
Key Features
• Technology Current Rating up to 1000A , Operating Voltage up to 630V
• Mechanical 38999 Series III or Bulldog breakaway connector interface, jam-nut, fl ange mount and inline connections, 500+ mating cycle durability
• Termination Crimp, screw or fl athead contact termination available.  Straight or right angled backshells available for strain relief and  360° EMC/RFI screening
• Safety IP2X, plastic cap on pin contact to prevent shock
• Environmental Aluminium, Stainless Steel or Aluminium Bronze shells.  Temperature range -55°C to +125°C, IP68 sealing, plating dependant, 500 Hrs Salt Spray.
• RoHS Compliant Zinc Cobalt and Zinc Nickel plating fi nishes available



The Amphenol Power Connectors incorporate the proven design of the Mil-DTL-38999 Series III  Tri-Start connectors with the evolving technology of the High Power RADSok® contacts.  This newly designed product is the future of power connectors enabling  customers to choose contacts ranging from 70 to 250 amps allowing more power in a smaller connector. Using  standard shell sizes for 38999 connectors will allow the Power Connectors to mate to existing mounting holes without changing the customer’s original design. 
Amphenol will also be incorporating our new alternate to Cadmium Plating called Durmalon. Durmalon is a  Nickel-PTFE that is proven to meet Coupling Torque, Shell to Shell Conductivity, and Durability tests required  by the MIL-DTL-38999 salt spray requirements.
RADSoK®  Technology Advantages
•  High Reliability Unique RADSok design and construction   technology create an electrical contact interface  that exceeds typical interconnect   requirements. Applications in aerospace,    medical, industrial, automotive, mining, off shore, and other harsh environments.
• Low Contact Engagement/Separation Forces The hyperbolic lamella socket contact  construction distributes normal forces over a  high percentage of the mating pin surface. This  creates a smooth, even engagement effort. This  force distribution also contributes to excellent  performance in vibration applications with   resistance to typical fretting corrosion.


High Vibration - Dualok

The Dualok represents the latest in high performance connector designs from Amphenol. Featuring a newly developed locking mechanism, the Dualok plug ensures rock-solid coupling and metal-to-metal bottoming in the most severe vibration environments. 
Dualok features and benefits include:
• Mates with standard D38999 receptacles and utilizes standard D38999 inserts.
• Designed to withstand and stay mated under vibration levels that exceed MIL-DTL-38999 levels
• Dualok stainless steel provides a weight savings of up to 42% compared to standard D38999 stainless steel designs
• Brand new size 7 plugs and receptacles
• Stainless steel, aluminum, composite, or aluminum bronze materials  of construction
• Dualok aluminum provides ~ 10% weight reduction over D38999 Aluminum
• Available in sizes 7 – 25
• Offering of new 7-2, 7-3 & 7-4 insert patterns
• Coupling mechanism that does not “settle” under vibration levels exceeding MIL-DTL-38999
• Metal-to-metal bottoming for maxium EMI shielding under extreme vibration


HD38999 High Density

The HD38999 family of connectors has 30% to 50% more contact density than the highest density Mil Spec 38999 connectors of its size. This series of connectors was  designed to utilize mil-specified 38999 components with the exception of the contacts and insert arrangements.  Utilizing existing mil-qualified 39029 size 23 contacts and 38999 insert materials, these connectors are essentially a drop-in replacement for the standard 38999 connector. This connector design benefits users in a couple of different ways. For those users who need to increase the amount of contacts in their application, the HD38999 series allows them to do so without increasing the size of their  connector. For users who are looking to decrease the overall size of their system, they can do so by using smaller shell sizes without decreasing the number of contacts. Amphenol has qualified this series of connectors to the  requirements of MIL-DTL-38999. Amphenol also  manufacturers this high density series in Filter, Hermetic and customized versions to fit our customer’s needs.  Please contact us if additional information is required.

HD38999 Connectors available styles:
• Aluminum
• Composite
• Stainless Steel
• Sealed (IP67)
• Filtered



Hermetic / Epoxy Sealed 38999 


Amphenol Aerospace is offering superior electrical performance plus the rugged design of a glass sealed hermetic connector.


Amphenol glass sealed hermetic connectors are available in a wide variety of Mil-Spec and custom configurations.

•Leakage rate of 1 x 10-7 cc of He/sec or less
•Fused glass insert in steel shell
•Options include:
•Special flanges
•PC board mounting stand-offs
•PC board mounting tails
•EMI Filtering
•Through bulkhead configurations
•Crimp termination


Amphenol epoxy sealed connectors are a light-weight alternative to glass sealed hermetic connectors for use in avionics and other weight-sensitive applications where a high level of sealing is required. Epoxy sealed connectors are an optimal solution when increasingly stringent sealing requirements must be met in radio and vetronics applications.

•Same epoxy as used in EMI filter connectors
•Less than 1 x 10-5 cc of He/sec leak rate
•Maintained after temperature cycling, 5 cycles -55 to +125°C
•Custom designs available with lower leak rates upon request
•Available in standard and custom configurations including PC tail, solder cup, and crimp termination, board mounting stand-offs, and thru-bulkhead configurations.


Amphenol Aerospace offers a lightweight 38999 Series III interconnect solution for sealed bulkhead applications.

These jam nut or wall mount style connectors offer lighter weights than glass fused steel hermetics. They feature 1x10-5 minimum leak rates when
properly installed. This, combined with crimp insertable contacts, allows quick and reliable termination using standard M39029/57 socket
contacts. Perfect for those pressure vessel or thru-bulkhead applications.


•Aluminum shells with Electroless nickel plating standard -Also available in Durmalon and O.D. Cadmium finishes. Steel available upon request
•Accessory threads sized for standard backshells
•Intermateable & inter-mountable with standard 38999 Series III plugs
•Extra thick panel mounting capable – Up to .375 in.
•Crimp termination using Amphenol’s UTS (Universal Termination System)
•Uses Amphenol’s standard “Filter Epoxy Compound” - 40 years of proven
•reliability and experience
•Skydrol and jet fuel resistance inserts, seals and backfill


38999 Fiber Optic & ARINC

Fiber Optics in MIL-DTL-38999 Series III Connectors Amphenol Aerospace offers a wide range of fiber optic  intercon nect solutions for use in the harsh environments found in military and aerospace applications. Amphenol Aerospace has established the rugged and reliable MIL-DTL-38999 as a com mon connector shell platform that houses a wide variety of fiber optic termini including MIL-PRF-29504 commercial equivalent*, HDF20, ARINC 801 and MT ferrules.

MIL-PRF-29504 supersedes MIL-T-29504.

MIL-DTL-38999 Series III Tri-Start connectors are available in various insert arrangements, materials and finishes to meet any type of environmental requirement. Our MIL-PRF-29504 style and HD20 termini can be combined with most of our copper contacts to create a large assortment of hybrid fiber/copper connector combinations.



You will find hereafter Amphenol  backshells for LJT (MIL-DTL-38999 series I / HE308), RNJ (HE308), RNJ LP, TV-CTV (MIL-DTL-38999 series III), SC39 and SJT (VG96912) connectors, as well as specific light weight backshells for JT(MIL-DTL-38999 series II) connectors. These rear accessories enhance the performance capabilities of the connectors for both general duty and severe environment applications.
Different technologies are used in order to ensure the following functions: - EMI shielding - cable retention - sealing
Main features
• Shell material - Aluminium alloy - Marine bronze - For composite, please consult us
• Finish - Olive drab cadmium plating - Electroless nickel plating - For others, please consult us
• 9 shell sizes per model
• Straight or right angled versions
• Working temperature - From – 65°C to + 175°C with olive drab cadmium plating - From – 65°C to + 200°C with electroless nickel plating
• French standard qualification capability (UTE 93422)