1. 📐 Engineering Drawings (or at Least a Sketch)

A technical drawing is the foundation of your cable design. Even a rough sketch is better than verbal instructions. It should include:

1. Overall cable length

2. Connector types and orientation

3. Wire gauge and number of conductors

4. Pin-to-pin configuration or wiring map

5. Breakouts, shielding, and strain relief design

Tip: If you don’t have a formal drawing, your EMS provider may help you create one—especially if you share reference photos or CAD files.

2. 🧪 Expected Performance & Testing Requirements

Define what “success” looks like for your cable. Your EMS partner needs to know how the assembly will be tested, and what performance standards it must meet. Common criteria include:

1. Continuity or insulation resistance test

2. Hi-pot (high potential) test for high-voltage cables

3. Pull or torque testing

4. Signal integrity (for data cables)

5. EMI shielding effectiveness

Be clear about pass/fail thresholds and if testing needs to be done on 100% of units or just a sample.

3. 🔁 Samples, Prototypes, or Similar References

If you’ve previously used a similar cable, providing a physical sample or photo will greatly speed up design alignment. Your EMS supplier can reverse-engineer or validate specs based on the sample, helping:

1. Reduce ambiguity

2. Confirm material compatibility

3. Ensure pinout and connector selection match

4. ��️ Environmental and Application Conditions

The end-use environment heavily influences cable selection—especially insulation and jacketing materials. Be prepared to share:

1. Operating temperature range

2. Waterproofing or moisture exposure (IP rating requirements)

3. Oil, solvent, or chemical exposure

4. Outdoor vs indoor usage

5. UV or flame resistance needs

The more your supplier knows, the better they can recommend suitable materials that balance performance and cost.

5. 📦 Delivery, Packaging, and Labeling Requirements

Even after the cables are assembled, logistics matter. You should also communicate:

1. Quantity per lot or reel

2. Special labeling or barcoding needs

3. Custom packaging (e.g., anti-static bags, coiled lengths, heat-sealed pouches)

4. Required certifications (RoHS, UL, ISO, etc.)

Final Thoughts

A successful cable assembly project doesn’t start on the production line—it starts with clear, complete communication.

By providing your EMS partner with the right drawings, test expectations, and application details upfront, you save time, reduce risk, and ensure the final product works exactly as expected.

If you're not sure where to begin, start with a sample or sketch—an experienced EMS team can guide you through the rest.