MIL-DTL-24308 D-Subminiature Connector Standards
Comprehensive Technical Specification, Classifications, Mechanical/Environmental Characteristics & Specification Sheets Directory
1. General Overview of the MIL-DTL-24308 Series
MIL-DTL-24308 defines polarized shell, rectangular, miniature, rack and panel electric connectors equipped with non-environmental pin or socket contacts. Widely recognized as the military D-subminiature (D-Sub) standard, these connectors are engineered for high-density, high-reliability interconnections across defense avionics, missile guidance systems, spaceflight instruments, ground support hardware, and industrial electronics. The polarization achieved through D-shaped trapezoidal metallic shells prevents mismating and provides robust physical contact protection.
1.1 Specification Classes & Application Environments
| Class Code | Description & Construction Type | Target Application & Operating Notes |
| Class G | General Purpose, Nonmagnetic limits not applicable | Standard military ground, naval, and rack/panel applications. |
| Class N | Nonmagnetic, low magnetic permeability | Airborne equipment, sensitive magnetic sensors, and electronic assemblies. |
| Class H | Hermetic seal, glass-to-metal sealed contacts | Pressurized compartments, vacuum chambers, and sealed enclosures. |
| Class D | Spaceflight Quality General Purpose | High reliability space missions requiring low outgassing and high integrity. |
| Class M | Spaceflight Quality Nonmagnetic | High reliability space missions requiring stringent nonmagnetic performance. |
| Class K | Spaceflight Quality Hermetic | Spaceflight payloads and sealed instruments needing space-qualified hermetic sealing. |
1.2 Shell Finishes & Material Coding
Connector shells are fabricated from steel, brass, aluminum, or stainless steel depending on the class. The specification identifies shell plating finishes using standardized suffix letter codes:
| Finish Code | Plating Type & Finish Treatment | Applicability & Environmental Notes |
| Code A | Pure Electrodeposited Aluminum | Classes G, N (RoHS compliant, space-grade alternative) |
| Code F | Cadmium Plating (with chromate conversion) | Classes G, N (Standard military finish; restricted in Army ground systems) |
| Code K | Zinc Nickel Plating | Classes G (RoHS compliant, high corrosion resistance) |
| Code P | Passivated Stainless Steel | Classes G, N, D, M, H, K (Corrosion resistant & nonmagnetic) |
| Code T | Nickel Fluorocarbon Polymer | Classes G (High lubricity, durable finish) |
| Code Z | Zinc Plating | Classes G (General commercial/defense substitution) |
| Code – (Dash) | Electroless Nickel or Gold | Code ‘-‘ signifies Nickel plating for Class D/G or Gold plating for Class M |
2. Mechanical and Technical Environmental Characteristics
MIL-DTL-24308 connectors must satisfy strict performance baselines under qualification testing per MIL-STD-202 and specification section 4.5. Key mechanical, electrical, and environmental ratings are detailed below.
| Characteristic Parameter | Specified Value / Standard Requirement | Test Condition / Class Application |
| Operating Temperature | -55°C to +125°C | All classes (Classes G, H, N, D, K, M) |
| Dielectric Withstanding Voltage (Sea Level) | 1,000 V rms (Classes G, D, M, N) 750 V rms (Classes H, K) 500 V rms (Type III) | 60 Hz test voltage (not working voltage) |
| Dielectric Withstanding Voltage (70,000 ft) | 325 V rms (Classes G, D, M, N) 175 V rms (Classes H, K) | High altitude pressure testing |
| Insulation Resistance | 5,000 Megohms minimum | Initial ambient conditions |
| Current Rating (Signal Contacts) | 7.5 Amps nominal (Size 20) 5.0 Amps / 3.0 Amps (Size 22D / 24 AWG) | Standard signal contacts per SAE AS39029 |
| Current Rating (Power Contacts) | 10 Amps (.078 dia) 40 Amps (.125 dia) | Combination insert arrangements (Size 8 power) |
| Initial Contact Resistance | 0.008 Ohms max (Size 20) 0.0005 Ohms max (Power Size 8) | Measured contact drop |
| Shielded Contact Impedance & Loss | 50 Ohms nominal Insertion Loss: -0.46 dB @ 1 GHz, -1.5 dB @ 2 GHz VSWR: 1.15 @ 1 GHz, 1.56 @ 2 GHz | Size 8 coaxial/shielded contacts in combination inserts |
| Hermetic Air Leakage | < 1 x 10^-7 cm^3/s of helium | Classes H and K tested at 1 atm differential |
2.1 Mechanical Shell Details, Contact Types & Mounting Hardware
The series comprises 6 standard shell sizes housing distinct contact layouts:
- Shell Sizes 1 to 5: Standard density (Size 20 contacts, 9 to 50 positions) and high density (Size 22D contacts, 15 to 78 positions).
- Shell Size 6: Maximum density housing 104 Size 22D contacts or 46W4 combination layouts.
- Termination Styles: Solder Cup, Crimp (rear-release/removable), Printed Wiring Board (PWB – Straight & Right Angle), and Insulation Displacement Connector (IDC).
- Hardware Assemblies: MIL-DTL-24308/25 (Male Screw-Lock Assemblies) and MIL-DTL-24308/26 (Female Screw-Lock Assemblies) provide vibration-proof locking.
3. Master Directory of MIL-DTL-24308 Specification Sheets
The table below details all specification sheets available in the project documentation. Each standard entry includes its connector type, gender, termination style, contact sizes, applicable classes, and key engineering selection details.
| Specification Standard | Connector Type | Description & Termination Style | Contact Sizes | Classes | Additional Engineering Information |
| MIL-DTL-24308 General | General Specification | D-Subminiature rectangular connectors, nonenvironmental | Size 20, 22D, 8, 16 | Classes G, N, H, D, M, K | Base performance & test standard for all specification sheets. |
| MIL-DTL-24308/1 | Receptacle (Socket) | Rack & Panel, General Purpose, Solder Cup | Size 20 | Classes G, D | Mates with /3, /4, /9, /24. Standard density (9-50 contacts). |
| MIL-DTL-24308/2 | Receptacle (Socket) | Rack & Panel, General Purpose, Crimp Type | Size 20, 22D | Classes G, D | Standard & high density (15-104 contacts). Uses M39029/63 contacts. |
| MIL-DTL-24308/3 | Plug (Pin) | Rack & Panel, General Purpose, Solder Cup | Size 20 | Classes G, D | Solder termination plug for panel/cable mount. |
| MIL-DTL-24308/4 | Plug (Pin) | Rack & Panel, General Purpose, Crimp Type | Size 20, 22D | Classes G, D | Crimp plug using M39029/58 pin contacts. |
| MIL-DTL-24308/5 | Receptacle (Socket) | Rack & Panel, Nonmagnetic, Solder Cup | Size 20 | Classes M, N | Low permeability nonmagnetic construction for space/avionics. |
| MIL-DTL-24308/6 | Receptacle (Socket) | Rack & Panel, Nonmagnetic, Crimp Type | Size 20, 22D | Classes M, N | Nonmagnetic crimp receptacle. High-rel space qualified (Class M). |
| MIL-DTL-24308/7 | Plug (Pin) | Rack & Panel, Nonmagnetic, Solder Cup | Size 20 | Classes M, N | Nonmagnetic solder plug. |
| MIL-DTL-24308/8 | Plug (Pin) | Rack & Panel, Nonmagnetic, Crimp Type | Size 20, 22D | Classes M, N | Nonmagnetic crimp plug. |
| MIL-DTL-24308/9 | Plug (Pin) | Hermetic, Solder Cup or Eyelet | Size 20, 22D | Classes H, K | Glass-to-metal hermetic seal (< 1×10^-7 cm^3/s leak rate). |
| MIL-DTL-24308/23 | Receptacle (Socket) | PWB Termination (Straight & Right Angle) | Size 20, 22D | Classes G, M, N, D | Printed wiring board socket receptacle. |
| MIL-DTL-24308/24 | Plug (Pin) | PWB Termination (Straight & Right Angle) | Size 20, 22D | Classes G, M, N, D | Printed wiring board pin plug. |
| MIL-DTL-24308/25 | Hardware Assembly | Screw-Lock Assembly, Male | N/A | All Classes | Male jackscrew assembly for connector retention. |
| MIL-DTL-24308/26 | Hardware Assembly | Screw-Lock Assembly, Female | N/A | All Classes | Female jackscrew receiver assembly. |
| MIL-DTL-24308/27 | Receptacle (Socket) | Insulation Displacement Connector (IDC) | Size 20 | Class G | Flat ribbon cable mass-termination socket. |
| MIL-DTL-24308/28 | Plug (Pin) | Insulation Displacement Connector (IDC) | Size 20 | Class G | Flat ribbon cable mass-termination pin plug. |
| MIL-DTL-24308/29 | Plug (Pin) | Combination Insert, Shell Size 1, PWB Type | Size 20 Signal + Size 8 Power/Shielded | Classes G, M, N, D | Combo layouts (2W2K, 5W1). 10A/40A power & 50 Ohm shielded. |
| MIL-DTL-24308/30 | Receptacle (Socket) | Combination Insert, Shell Size 1, PWB Type | Size 20 Signal + Size 8 Power/Shielded | Classes G, M, N, D | Mates with /29. Combo PWB socket receptacle. |
| MIL-DTL-24308/31 | Plug (Pin) | Combination Insert, Shell Size 2, PWB Type | Size 20 Signal + Size 8 Power/Shielded | Classes G, M, N, D | Combo layouts (3W3, 3WK3, 7W2, 11W1). |
| MIL-DTL-24308/32 | Receptacle (Socket) | Combination Insert, Shell Size 2, PWB Type | Size 20 Signal + Size 8 Power/Shielded | Classes G, M, N, D | Mates with /31. |
| MIL-DTL-24308/33 | Plug (Pin) | Combination Insert, Shell Size 3, PWB Type | Size 20 Signal + Size 8 Power/Shielded | Classes G, M, N, D | Combo layouts (5W5, 9W4, 13W3, 17W2, 21W1). |
| MIL-DTL-24308/34 | Receptacle (Socket) | Combination Insert, Shell Size 3, PWB Type | Size 20 Signal + Size 8 Power/Shielded | Classes G, M, N, D | Mates with /33. |
| MIL-DTL-24308/35 | Plug (Pin) | Combination Insert, Shell Size 4, PWB Type | Size 20 Signal + Size 8 Power/Shielded | Classes G, M, N, D | Combo layout (8W8). |
| MIL-DTL-24308/36 | Receptacle (Socket) | Combination Insert, Shell Size 4, PWB Type | Size 20 Signal + Size 8 Power/Shielded | Classes G, M, N, D | Mates with /35. |
| MIL-DTL-24308/37 | Plug (Pin) | Combination Insert, Shell Size 5, PWB Type | Size 20 Signal + Size 8 Power/Shielded | Classes G, M, N, D | Combo layouts (24W7, 36W4, 43W2, 47W1). |
| MIL-DTL-24308/38 | Receptacle (Socket) | Combination Insert, Shell Size 5, PWB Type | Size 20 Signal + Size 8 Power/Shielded | Classes G, M, N, D | Mates with /37. |
| MIL-DTL-24308/39 | Plug (Pin) | Combination Insert, Shell Size 6, PWB Type | Size 20 Signal + Size 8 Power/Shielded | Classes G, M, N, D | Combo layout (46W4). |
| MIL-DTL-24308/40 | Receptacle (Socket) | Combination Insert, Shell Size 6, PWB Type | Size 20 Signal + Size 8 Power/Shielded | Classes G, M, N, D | Mates with /39. |
| MIL-DTL-24308/41 | Plug (Pin) | Combination Insert, Shell Size 1, 2, 4, Crimp | Size 22 Signal + Size 8 & 16 Power/Shielded | Classes G, M, N, D | High density combo layouts (8W2, 19W1, 45W2). Uses AS39029/58 contacts. |
| MIL-DTL-24308/42 | Receptacle (Socket) | Combination Insert, Shell Size 1, 2, 4, Crimp | Size 22 Signal + Size 8 & 16 Power/Shielded | Classes G, M, N, D | Mates with /41. High density combo receptacle. Uses AS39029/57 contacts. |
4. Engineering Selection Summary
When specifying MIL-DTL-24308 connectors for system integration, design engineers should follow a structured selection process:
- Determine Environmental & Reliability Requirements: Select Class G/N for standard military or Class D/M/K for spaceflight applications requiring low outgassing and high reliability.
- Select Shell Finish: Choose Cadmium (F) for standard defense corrosion resistance, Zinc-Nickel (K) or Aluminum (A) for RoHS compliance, or Stainless Steel (P) for harsh nonmagnetic environments.
- Choose Contact Termination Method: Select Crimp contacts for field repairability, Solder Cup for fixed wiring harnesses, PWB (Straight/Right Angle) for direct circuit board integration, or IDC for ribbon cable assembly.
- Evaluate Insert Configuration: Choose standard signal layouts (Size 20/22D) or combination insert arrangements (Size 8 power/shielded contacts) to combine power, signal, and RF coaxial lines within a single D-Sub shell.