220-1201 Practice Question: A technician is installing a new network switch…

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

• ✗

  Single-mode fiber (OS2)

  Why it's wrong here

  Single-mode fiber (OS2) is designed for transmitting data over very long distances, often kilometers, using a single path for light. However, 10GBASE-SR (Short Reach) transceivers are specifically engineered to operate with multimode fiber, utilizing an 850nm Vertical-Cavity Surface-Emitting Laser (VCSEL) optimized for its larger core. Attempting to use a 10GBASE-SR module with single-mode fiber would result in a link failure due to incompatible optical characteristics and power budget, requiring a different transceiver standard like 10GBASE-LR for single-mode.

• ✓

  Multimode fiber (OM3)

  Why this is correct

  Multimode fiber (OM3) is the correct choice for 10GBASE-SR connections because the 'SR' (Short Reach) standard is specifically designed to operate over multimode fiber. OM3 fiber is an optimized multimode fiber type that supports 10 Gigabit Ethernet transmission up to 300 meters, making it ideal for inter-building or intra-building connections within a data center or campus environment. Its larger core diameter allows for the use of less expensive LED or VCSEL light sources, which are typically found in 10GBASE-SR transceivers.

• ✗

  Cat6a twisted pair

  Why it's wrong here

  Cat6a twisted pair is a copper cabling standard, not a fiber optic medium, and is fundamentally incompatible with a 10GBASE-SR fiber module. While Cat6a can support 10 Gigabit Ethernet (10GbE) over distances up to 100 meters, it requires specific 10GBASE-T transceivers, which typically use an RJ45 connector, or network cards with integrated 10GBASE-T ports. A 10GBASE-SR module, designed for fiber, would have LC or SC connectors and cannot physically or electrically interface with Cat6a copper cabling.

• ✗

  Coaxial cable

  Why it's wrong here

  Coaxial cable is an entirely different type of cabling, primarily used for traditional cable television, broadband internet access (DOCSIS), or older networking standards like 10BASE2/5. It is not designed for modern high-speed Ethernet connections like 10GBASE-SR, which explicitly specifies fiber optic cabling. Coaxial cable uses a central conductor surrounded by an insulating layer, braided shield, and outer jacket, making it physically and electrically incompatible with the optical signals and connectors used by 10GBASE-SR fiber transceivers.

Go deeper

Related to this question