J599 Series Circular Military Connectors
GJB599B / MIL-DTL-38999 Series III
Product Overview
The J599 Series Circular Connectors are manufactured in accordance with GJB599B (MIL-DTL-38999 Series III) standards and are designed for mission-critical electrical interconnections in military, aerospace, naval, and industrial applications.
Featuring a three-start threaded quick-coupling system with an anti-loosening mechanism, these connectors provide exceptional reliability in harsh environments. Their compact size, lightweight construction, high contact density, removable crimp contacts, and superior EMI/RFI shielding make them ideal for demanding applications requiring long-term performance.
The J599 series supports standard signal contacts, power contacts, fiber optic contacts, coaxial contacts, and shielded contacts, offering excellent flexibility for complex electrical systems.
Key Features
- Qualified to GJB599B / MIL-DTL-38999 Series III
- Three-start threaded quick coupling
- Anti-decoupling locking mechanism
- Compact and lightweight design
- High contact density
- Superior EMI/RFI shielding
- Removable crimp contacts
- Polarized keying to prevent mismating
- Compatible with signal, power, coaxial, shielded, and fiber optic contacts
- Excellent resistance to vibration, shock, moisture, dust, and corrosion
- Designed for long service life in extreme operating environments
Applications
Ideal for:
- Military Electronics
- Aerospace & Avionics
- Naval Systems
- Radar Equipment
- Defense Vehicles
- Communication Systems
- Industrial Automation
- Railway Electronics
- Test & Measurement Equipment
- Harsh Environment Electrical Systems
Operating Environment
Designed for reliable operation under:
- Severe vibration
- Mechanical shock
- Rain and moisture
- Sand and dust
- Salt spray
- High and low temperatures
- Fuel, hydraulic fluid, and solvent exposure
Materials
| Component | Material |
|---|---|
| Shell | Aluminum Alloy, Stainless Steel, or Titanium Alloy |
| Insulator | Thermosetting or Thermoplastic Plastic |
| Sealing Body & O-Rings | Silicone Rubber |
| Contacts | Gold-Plated Copper Alloy |
Available contact termination methods:
- Crimp
- Solder
- Printed Circuit Board (PCB)
Available Surface Finishes
| Code | Finish |
|---|---|
| W | Olive Drab Cadmium Plating |
| F | Electroless Nickel |
| K | Stainless Steel Passivation |
| FT | Satin Cadmium Plated Aluminum Alloy |
| TA | Titanium Alloy |
Mechanical Performance
| Parameter | Specification |
|---|---|
| Mechanical Life | ≥500 Mating Cycles |
| Shock Resistance | 300 g Peak Half-Sine, 3 ms |
| Sine Vibration | 60 g |
| Random Vibration (High Temperature) | 41.7 g RMS |
| Random Vibration (Ambient Temperature) | 49.5 g RMS |
Electrical Performance
Withstand Voltage
| Service Class | Sea Level | 21,000 m Altitude |
|---|---|---|
| M | 1300 V | 800 V |
| N | 1000 V | 600 V |
| I | 1800 V | 1000 V |
| II | 2300 V | 1000 V |
Note: Voltage ratings vary according to the contact arrangement.
Contact Ratings
| Contact Size | Diameter | Contact Resistance | Rated Current |
|---|---|---|---|
| 22D | 0.76 mm | ≤12 mΩ | 5 A |
| 20 | 1.00 mm | ≤5 mΩ | 7.5 A |
| 16 | 1.60 mm | ≤2.5 mΩ | 13 A |
| 12 | 2.40 mm | ≤1.5 mΩ | 23 A |
| 10 | 3.15 mm | ≤1.0 mΩ | 40 A |
Insulation Resistance
- ≥5000 MΩ @ 500 VDC
Shell Conductivity
| Finish | Conductivity |
|---|---|
| W | 2.5 mV |
| F / FT | 1.0 mV |
| K / TA | 10 mV |
EMI/RFI Shielding Performance
| Frequency Range | Minimum Shielding Effectiveness |
|---|---|
| 100 MHz – 1 GHz | ≥85 dB (Class F & W) |
| 1 GHz – 10 GHz | ≥65 dB (Class F) |
| 1 GHz – 10 GHz | ≥50 dB (Class W) |
Coaxial Contact Capability
For Size #8 Dual Coaxial Contacts:
- Frequency Bandwidth: 0–20 MHz
- Rated Voltage:
- 500 VAC (Sea Level)
- 125 VAC (21,000 m Altitude)
- Voltage Drop:
- Inner & Middle Contacts: ≤55 mV @ 1 A
- Outer Contact: ≤75 mV @ 12 A
Environmental Performance
| Parameter | Specification |
|---|---|
| Operating Temperature (Class W) | -65°C to +175°C |
| Operating Temperature (Class F/K/FT/TA) | -65°C to +200°C |
| Salt Spray Resistance (W) | 500 Hours |
| Salt Spray Resistance (K/TA) | 1000 Hours |
| Salt Spray Resistance (F) | 48–96 Hours |
| Salt Spray Resistance (FT) | 96 Hours |
| Moisture Resistance | MIL-DTL-38999 Qualified |
| Sealing | Low-pressure sealing compliant with MIL-DTL-38999 |
| Chemical Resistance | Resistant to fuels, hydraulic fluids, coolants, and industrial solvents |
Compatible Contact Types
- Signal Contacts
- Power Contacts
- Fiber Optic Contacts (Sizes 12#, 16#, and 20#)
- Coaxial Contacts (Sizes 8#, 10#, and 12#)
- Shielded Contacts
Product Advantages
- Compliant with MIL-DTL-38999 Series III international military standards.
- Compact, lightweight, and high-density design.
- Excellent EMI/RFI shielding performance.
- High resistance to shock, vibration, moisture, and corrosion.
- Removable contacts for easy maintenance.
- Available in multiple shell materials and surface finishes.
- Supports signal, power, fiber optic, and coaxial applications.
- Designed for long-term reliability in mission-critical environments.






