Communication cables are judged by a different standard than power wiring: their job is not to deliver energy but to deliver a signal intact. That single difference reorders every design priority — geometry, shielding and impedance replace ampacity and voltage drop. This guide organizes the main cable families and explains how to choose among them.
Twisted Pair: The Workhorse
Twisted-pair construction cancels noise by exposing both conductors of a differential signal to interference almost equally. Category-rated data cables (Cat5e through Cat8) add controlled twist rates and pair spacing to meet bandwidth targets, while industrial twisted-pair — often shielded — carries RS-485, CAN and fieldbus traffic where raw bandwidth matters less than noise immunity in electrically hostile cabinets. Key selection points: match the category or standard the protocol requires, shield according to environment (our shielded cable analysis covers the options), and terminate shields per the system's grounding scheme rather than by habit.
Coaxial Cable: Controlled Impedance
Coax keeps the signal inside a precisely defined geometry — center conductor, dielectric, shield — so its impedance (50Ω for RF, 75Ω for video) is stable along the run. Selection revolves around loss at the operating frequency, flexibility and the connector system: an excellent cable with a poorly installed connector is a bad cable. For instrument and RF patching, our RG402 coaxial guide shows how semi-rigid constructions buy performance with handling constraints.
Hybrid Power + Signal Assemblies
Modern machines and vehicles increasingly want one cable doing both jobs: powering a camera while carrying its video, or feeding an antenna while carrying its control bus. Hybrid assemblies combine power cores with individually shielded signal pairs under one jacket, with internal separation and, where needed, individual shields. The engineering discipline is in the details: enough distance or shielding between power and signal cores, verified by test on the finished assembly rather than assumed from the datasheet.
Fiber and Copper: When Each Wins
Fiber wins on distance, bandwidth and total isolation from electrical noise; copper wins on cost, connector simplicity and the ability to deliver power along with data. Most real systems are hybrids — fiber for backbone runs, copper for the last meters. Our fiber optic harness guide covers the harness-level considerations when fiber enters a cable assembly program.
Connector and Termination Discipline
Communication assemblies fail at terminations more often than in the cable body: untwist-too-far in Cat terminations destroys pair balance, over-crimping deforms coax dielectric and shifts impedance, and pigtail shield terminations leak noise exactly at the frequencies that matter. A manufacturer building communication harnesses must control all three — with process documentation, not good intentions.
Selection Checklist
- Protocol/bandwidth requirement → cable category or standard
- Environment → jacket material and shield type
- Run length and data rate → loss budget, impedance control
- Power + signal together? → hybrid construction with separation
- Mating cycles and handling → connector class and strain relief
Kaweei manufactures communication cable assemblies — shielded data harnesses, coaxial and hybrid power/signal builds — tested to documented electrical and RF requirements. Contact us with your protocol and environment details for a quotation.