The part number **D38999/26FJ46PCL** refers to a high-reliability circular connector built to military specifications (MIL-DTL-38999 Series III). These connectors are designed for harsh environments, such as aerospace, defense, and marine applications. --- ### Part Number Breakdown The following table breaks down each segment of the part number according to the MIL-DTL-38999 standard: | Segment | Code | Description | | :--- | :--- | :--- | | **Series** | D38999/26 | **Series III Straight Plug** (with RFI shielding) | | **Service Class** | F | **Electroless Nickel** (Aluminum shell, conductive, -65°C to +200°C) | | **Shell Size** | J | **Size 25** (The largest standard shell size) | | **Insert Arrangement** | 46 | **46 Contacts** (Combination of various gauges) | | **Contact Type** | P | **Pin** (Male contacts) | | **Polarization** | C | **C Position** (Alternate keying to prevent cross-mating) | | **Modification** | L | **Less Contacts** (Connector body supplied without the actual pins) | --- ### Technical Specifications #### 1. Physical Design * **Coupling:** Triple-start threaded coupling with a self-locking mechanism to prevent loosening under high vibration. * **Shell Material:** Aluminum alloy with an electroless nickel finish, providing excellent EMI/RFI shielding. * **Insert:** High-grade plastic/silicone with rear-release contact retention. #### 2. Contact Arrangement (46) The "46" arrangement in Shell Size 25 typically consists of a mixed density layout: * **40 contacts** of Size 22D (Signal/Data). * **4 contacts** of Size 16 (Power). * **2 contacts** of Coaxial/Twinax (High-speed data). #### 3. Environmental Resistance * **Temperature Range:** -65°C to +200°C. * **Durability:** Minimum 500 mating cycles. * **Ingress Protection:** Moisture and salt spray resistant (48 hours for nickel finish). * **Vibration/Shock:** Designed to withstand extreme mechanical stress found in jet engines and missile systems. --- ### Important Usage Note: The "L" Suffix The **"L"** at the end of the part number is critical for procurement. It signifies that the connector is sold as a "Large Lead-in" or **"Less Contacts"** version. This means the housing and insulator are provided, but the gold-plated crimp pins must be purchased separately. This allows engineers to choose specific contact plating or wire termination types.