You must interconnect two separate 10Base-T Ethernet networks located in different buildings about 1,000 meters apart. Which physical media is most appropriate for a reliable link at this distance?

Introduction / Context:
10Base-T specifies twisted-pair copper with a maximum segment length of 100 meters. Building-to-building links at 1 km require a medium with far lower attenuation and immunity to electrical interference and lightning potential differences. Fiber-optic links are the industry standard for campus interconnects of this distance.

Given Data / Assumptions:

• Distance ≈ 1,000 meters between buildings.
• Need to link two 10Base-T Ethernet networks reliably.
• Outdoor/OSP considerations (grounding, surge) favor non-conductive media.

Concept / Approach:

Twisted pair and 10Base-T copper are limited to 100 m without active devices. Coaxial 10Base2/10Base5 is obsolete and also distance-limited and electrically conductive. Fiber provides high bandwidth, low loss over kilometers, and galvanic isolation between buildings, reducing surge and ground loop risks. IR wireless is highly line-of-sight sensitive and weather-dependent, unsuitable for dependable backbone links.

Step-by-Step Solution:

Verification / Alternative check:

Campus networks universally use multimode or single-mode fiber for 300 m–10 km spans; successful deployments confirm fiber as the best practice for ~1 km.

Why Other Options Are Wrong:

Type 1 STP: Token Ring cabling; copper distance limits and interbuilding grounding issues.

RG-58 A/U: 10Base2 thin Ethernet; distance and reliability constraints.

Wireless infrared: Weather/line-of-sight constraints; not robust for 1 km enterprise backbones.

None: Incorrect because fiber is the correct medium.

Common Pitfalls:

Trying to daisy-chain copper switches across buildings; ignoring electrical code and surge risks of metallic cabling between facilities.

Final Answer:

Fiber-optic cable