D38999 Series III Connectors

d38999 series iii conesys

D38999 Series III circular connectors are high-performance cable to panel interconnects suitable for military, aerospace and harsh environment applications. NYKCS is a fully approved value-add distributor (VAD) for Conesys. Therefore, we can assemble MIL-DTL-38999 III connectors to meet your specific requirements. Contact us today for the best price and fast delivery.

The MIL-DTL-38999 Series III  range of military connectors (commonly known as D38999 III) features a number of body styles, contact termination options, body materials and platings. Consequently, these connectors suit a wide variety of electronic, mechanical and environmentally demanding applications. Up to 128 contacts are available in a number of defined high-density insert arrangements with a reliable tri-start coupling.

Price and delivery

We are the most competitively priced supplier of approved MIL-DTL-38999 Series III connectors. NYKCS is fully approved to AS9100 Rev D and can assemble to meet your requirements. Contact us now for fast turnaround in 47 hours* from receipt of order.

* 1 hour removed through streamlined processes!

Conesys MIL-DTL-38999 Series III

Popular in this Category

D38999 2ZE06PA ConnectorD38999/20ZE06PA

  • Wall Mount Receptacle
  • Aluminium Shell
  • Black Zinc Nickel Finish
  • 6 Size 12 Contacts
  • Pin Contacts
  • ‘A’ Keyway

D38999_24FF11SD ConnectorD38999/24FF11SD

  • Jam Nut Receptacle
  • Aluminium Shell
  • Electroless Nickel Finish
  • 11 Size 16 Contacts
  • Socket Contacts
  • ‘D’ Keyway

D38999_26WD19SN ConnectorD38999/26WD19SN

  • RFI Grounding Plug
  • Aluminium Shell
  • Cadmium Olive Drab Finish
  • 19 Size 20 Contacts
  • Socket Contacts
  • ‘N’ Keyway


  • Jam Nut Receptacle
  • Black Zinc Nickel Finish
  • Shell Size D
  • 19 size 20 Pin Contacts
  • 'A' keyway


  • Free Plug
  • Black Zinc Nickel Finish
  • Shell Size D
  • 19 Size 20 Socket Contacts
  • 'A' Keyway


  • Wall Mount Receptacle
  • Cadmium Olive Drab Finish
  • Shell Size A
  • 3 size 20 Socket Contacts
  • 'N' Keyway


  • Free Plug
  • Cadmium Olive Drab Finish
  • Shell Size A
  • 3 size 20 Pin Contacts
  • 'N' Keyway

How to Define a D38999 Part Number

Looking for a Part Number?

D38999 Value-Add Assembly

value add assembly d38999 part mark

In house assembly

In-house assembly enables NYKCS to supply a huge range of approved components quickly and efficiently. Thereby meeting each customer’s specific requirement for MIL-DTL 38999 Series III.

VAD Approved Connector Assembly

Approved to AS9100 Rev D

The assembly facility is fully approved to AS9100 Rev D. This provides end to end traceability and documentation that meets the needs of the most demanding supply chain.

value add assembly d38999 kitting from stores

Flexible scheduling

The latest workflow management solutions enable NYKCS to support complex order books and short production runs of MIL-DTL-38999 alongside our extensive range of mil-spec interconnect products.

Product Features

  • Sizes and Inserts: 9 shell sizes, 52 insert arrangements;
  • Plating: Black Zinc Nickel, Olive Drab, Electroless Nickel;
  • Coupling: Tri-start threaded coupling design, rapid advance, self-locking and full-mate indicator, keyed and Scoop-Proof;
  • EMI Shielding: up to 65dB minimum at 10 GHz;
  • Mating Speed: 360°, one full turn to full mate;
  • Test Voltage (Sea Level): up to 2300 VRMS;
  • Suggested Operating Voltage (Sea Level): up to 900V AC(RMS), 1250V DC;
  • Operating Temperature: -65°C to +200°C (-85°F to +392°F) depending on shell material and finish;
  • Vibration: Wired and mated connectors withstand the following vibration levels:
    • Sine vibration where connector samples with simulated accessory load are subjected to simple harmonic motion from 10 to 2000 Hz in three mutually perpendicular axes in 20-minute sweeps for 12 hours in each axis at a velocity of 254 mm/sec from 10-50 Hz, displacement of 1.5 mm from 50-140Hz and acceleration of 60G from 140-2,000Hz;
    • Random Vibration per MIL-STD-1344, method 2005, test condition V at ambient temperature and test condition VI letter “J” at elevated temperature.
  • Fluid Resistance: Connectors resist specified immersions in MIL-PRF-7808, MIL-PRF-23699, MIL-PRF-5606, M2-V Chevron oil, Coolanol 25, MIL-DTL-83133 (JP-8), MIL-DTL-5624 (JP-4, JP-5), SAE-AMS1424 Type I, and other solvents and cleaning agents;
  • Shock: Pulse of approximate half sine wave of 300 G ± 15 percent magnitude with a duration of 3 ± 1 milliseconds applied in three axes;
  • Corrosion Resistance: Military Classes K, W and S, withstand 500-hour salt spray. Class F withstands 48-hour salt spray, Commercial RoHS Classes: BN*, BZ*, ZC*. Consult factory for T and Z class availability;
  • Durability: Minimum of 500 mating cycles.
d38999 iii circular connector receptacle
D38999 Series III plug zinc

Data Sheets

Conesys MIL-DTL-38999 Series III SpecificationConesys MIL-DTL-38999 Series III Specification

MIL-DTL-38999 Series III Connectors Product SheetMIL-DTL-38999 Series III Connectors Product Sheet

AS85049 Product SheetAS85049 backshells for MIL-DTL-38999 Series III Product Sheet

M39029 Contacts Product SheetM39029 contacts for MIL-DTL-38999 Series III Product Sheet

Quality Approvals

Conesys Franchised Distributor CertificationConesys Franchised Distributor Certification

DLA 38999 Documentation - VQP-18-031857DLA 38999 Documentation - VQP-18-031857

How to Define a d38999 Part Number

1.  Decide how and where the connector will be used. The available Shell Style's support various mounting options to suit your application.

2. Select the appropriate Service Class to support the environmental demands of your application.

3. Define the electrical requirements of the connector. The Shell Size and Contact Arrangement will be dictated by your circuit demands.

4. Select the Contact Style based on which half of your circuit is active i.e. whether your connector should have Pins or Sockets.

5.  Define if your connector needs a Polarising Position or insert N for none. This prevents mismating with similar neighbouring connectors.

The tables below will assist you to construct an official mil-spec part number for a MIL-DTL-38999 series III connector. Many of the connector OEM’s have their own proprietary part numbers which we can cross-reference to and from the mil part numbers. NYK Component Solutions assembles in-house for Conesys and is also a distributor for other leading OEM’s. We are in a unique position to provide unbiased advice for you to meet your technical and logistical requirements.

We have a very useful part number builder which also gives the mating half. Click below to try it out.

Part Number Breakdown Tables

MIL-DTL-38999 Series III

Example Part Number: D38999/20FA35PA


Range D38999 20 F A 35 P A
Shell Style D38999/20 Wall Mount Receptacle
D38999/24 Jam Nut Receptacle
D38999/26 RFI Self Locking Plug
Service Class and Finish F Electroless Nickel, Aluminium Alloy Shell
W Olive Drab Cadmium over Nickel, Aluminium Alloy Shell
Z Zinc Nickel, Aluminium Alloy Shell
K Stainless Steel Shell, passivated with firewall insert
S Stainless Steel Shell, electrodeposited Nickel with firewall insert
Shell Size A=9, B=11, C=13, D=15,E=17, F=19, G=21, H=23, J=25
Insert Arrangement See Insert Configurations by Shell Size Table
Contacts P Crimp Pin
S Crimp Socket
A Less Pins
B Less Sockets
Polarization N Normal
A,B,C,D (B&C not available in size 9)


D38999 Shell Style Options
D38999 III Shell Style Options

MIL-DTL-38999 Series III Insert Configurations by Shell Size

Insert Configurations by Shell Size (A1 through F32)

Shell Size - Insert Config. Service Rating Total Contacts Contact Size
22D 22M 22 20 16 12 10 8
A1 M 1 1T
A35 M 6 6
A98 I 3 3
B2 I 2 2C
B4 I 4 4
B5 I 5 5
(B13) M 13 13
B35 M 13 13
B98 I 6 6
B99 I 7 7
C4 I 4 4C
C8 I 8 8
(C22) M 22 22
C35 M 22 22
C98 I 10 10
D5 II 5 5C
D15 I 15 1 4 1C
D18 I 18 18
D19 I 19 19
D35 M 37 37
D97 I 12 8 4C
E2 M 39 38 1T
E6 I 6 6
E8 II 8 8C
E26 I 26 26
E35 M 55 55
(E55) M 55 55
E99 I 23 21 2C
F11 II 11 11C
F18 M 18 14 4T
F28 I 28 26 2C
F30 I 30 29 1C
F32 I 32 32


parenthesis ( ) : indicates inactive for new designs
C: available as coax or standard contacts
S: size 12A shielded contacts
T: Twinax contacts

Insert Configurations by Shell Size (F35 through J90)

Shell Size - Insert Config. Service Rating Total Contacts Contact Size
22D 22M 22 20 16 12 10 8
F35 M 66 66
F45 M 67 67
(F66) M 66 66
(G1) M 79 79
G11 I 11 11C
G16 II 16 16C
G24 I 24 24
G25 I 25 25
G27 1 27 27
G35 M 79 79
G39 I 39 37 2C
G41 I 41 41
G75 M 4 4T
(H1) M 100 100
H21 II 21 21C
H32 I 32 32
H34 I 34 34
H36 I 36 36
H53 I 53 53
H55 I 55 55
H97 I 16 16
H99 II 11 11
(J1) M 128 128
(J2) M 100 100
J4 I 56 48 8C
J7 M 99 97 2T
J8 M 8 8T
J11 I 11 2 9
J19 I 19 19C
J20 I 30 10 13F 4C 3T
J24 I 24 12C 12C
J29 I 29 29C
J35 M 128 128
J43 I 43 23 20C
J46 I 46 40 4 2C
J61 I 61 61
J90 I 46 40 4 2T

MIL-DTL-38999 III LayoutsMIL-DTL-38999 Series III Insert Arrangements

Contact Ratings

For information about the maximum contact rating for d38999 III connectors please see the table below:

Contact Size Test Current (A) Maximum Millivolt Drop
Crimp Solder
Standard Hermetic Standard Hermetic
22M 3 2 30 20 60
22D 5 40
22 5 3 40 20 85
20 7.5 5 35 20 60
16 13 10 25 20 85
12 23 17 25 85


Shell Size Key and Keyway Arrangement Identification Angle Rotation Letter - Receptacle or Plug
A(9) N 105 140 215 265
A 102 132 248 320
B 80 118 230 312
C 35 140 205 275
D 64 155 234 304
E 91 131 197 240
B(11), C(13) and D(15) N 95 141 208 236
A 113 156 182 292
B 90 145 195 252
C 53 156 220 255
D 119 146 176 298
E 51 141 184 242
E(17), F(19), G(21), H(23) and J(25) N 80 142 196 293
A 135 170 200 310
B 49 169 200 244
C 66 140 200 257
D 62 145 180 280
E 79 153 197 272
d38999 III keying positions
D38999 III keying positions

Polarization Notes: Numbers in table are the angle of rotation in degrees (see Keying Positions diagram).

  • from main key looking clockwise onto the front face of the plug
  • from main keyway looking anticlockwise onto the front face of the receptacle

Keyway identification ‘N’ is normal.

Insert arrangements do not rotate with the main keyway.

Crimp Tool Reference Table

Contact Type Size of Contacts Contacts Filler Plugs Plastic Tool Insertion/Removal Metal Tool Insertion Metal Tool Removal Crimp Tool Positioner- Turret Head Second Crimp Tool
Pin 22D M39029/58-360 MS27488-22-1 M81969/14-01 M81969/8-01 REV B M81969/8-02 REV B M22520/2-01 M22520/7-07
Socket 22D M39029/56-348 MS27488-22-1 M81969/14-01 M81969/8-01 REV B M81969/8-02 REV B M22520/2-01 M22520/7-05
Pin 20 M39029/58-363 MS27488-20-1 M81969/14-10 M81969/8-05 M81969/8-06 M22520/1-01 M22520/7-08
Socket 20 M39029/56-351 MS27488-20-1 M81969/14-10 M81969/8-05 M81969/8-06 M22520/1-01 M22520/7-08
Pin 16 M39029/58-364 MS27488-16-1 M81969/14-03 M81969/8-07 M81969/8-08 M22520/1-01 M22520/7-04
Socket 16 M39029/56-352 MS27488-16-1 M81969/14-03 M81969/8-07 M81969/8-08 M22520/1-01 M22520/7-04
Pin 12 M39029/58-365 MS27488-12-1 M81969/14-04 M81969/8-09 M81969/8-10 M22520/1-01 M22520/1-04
Socket 12 M39029/56-353 MS27488-12-1 M81969/14-04 M81969/8-09 M81969/8-10 M22520/1-01 M22520/1-04
Pin 8 Twinax M39029/90-529 MS27488-8-1 M81969/14-12 M81969/46-06 M81969/14-12 M22520/2-01 M22520/2-37 M22520/5-01
Socket 8 Twinax M39029/91-530 MS27488-8-1 M81969/14-12 M81969/46-06 M81969/14-12 M22520/2-01 M22520/2-37 M22520/5-01


Integrated Backshell D38999 Connectors

Built to conform with the MIL-DTL-38999 series III specification integrated backshell connectors are fully intermateable and interchangeable with D38999 III products. These connectors offer the performance advantages of D38999 with the following benefits over a traditional connector/backshell pairing:

  • quicker assembly;
  • space saving;
  • lower weight;
  • time-saving during ordering;
  • reduced inventory holding.

The one-piece shell construction completely integrates the straight backshell enabling screen termination by either band or spring. They are manufactured in both aluminium and stainless steel with various plating options available, including Black Zinc Nickel across the 3 shell styles.

integrated backshell d38999 iii

Integrated Backshell Part Number Development Table

Conesys d38999 iii integrated part number table download

Ready to find out more?

Contact us today for a free quote!

Hybrid black backshell


Need accessories? These circular connectors can be ordered with a very broad range of compatible accessories, be it a simple strain relief clamp, a fully sealed RFI/EMI compatible backshell or a custom design to suit a specific requirement. We can supply your connector backshell, as well as your connector.

NYKCS stocks a comprehensive range of circular connector backshells and protective caps (D38999-32 and D38999-33) from EMCA Electro-mechanic to suit the customers’ specific requirements. For more information contact the team or visit the relevant product page.