220-1201 Practice Question: A small office is upgrading from 100Base-TX to…

Answer analysis

Option-by-option breakdown

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

• ✗

  The cable runs are too long for 1000Base-T.

  Why it's wrong here

  The standard distance limitation for 1000Base-T (Gigabit Ethernet over copper) is 100 meters (328 feet) when using Category 5e or higher cabling. A 50-meter run is well within this specification, ensuring reliable signal transmission without excessive attenuation or crosstalk that would cause intermittent connectivity issues due to length alone. Therefore, cable length is not the cause of intermittent loss in this scenario.

• ✗

  The T568B wiring standard is incompatible with 1000Base-T.

  Why it's wrong here

  Both T568A and T568B are industry-standard wiring schemes for RJ-45 connectors used in structured cabling, including Ethernet. T568B is widely adopted and fully supports 1000Base-T, which utilizes all four twisted pairs for simultaneous bidirectional communication. Incompatibility with the wiring standard itself would result in no connection or a severely degraded, consistent issue, not intermittent loss.

• ✓

  The terminations are not fully seated or have poor contact on some pairs.

  Why this is correct

  1000Base-T (Gigabit Ethernet) uniquely requires all four twisted pairs within a Category 5e or higher cable to transmit and receive data simultaneously, unlike 100Base-TX which only uses two pairs. If one or more pairs have poor contact due to improper termination (e.g., a partially seated RJ-45 connector or poorly punched down keystone jack), the connection will struggle to establish or maintain a stable 1000 Mbps link, often falling back to 100 Mbps or experiencing intermittent disconnections as the system attempts to negotiate the higher speed.

• ✗

  The network switch ports are set to 100 Mbps full duplex.

  Why it's wrong here

  If the network switch ports were explicitly configured to 100 Mbps full duplex, the connected devices would reliably operate at that speed. While this would prevent the desired 1000 Mbps upgrade, it would result in a stable, albeit slower, connection rather than intermittent loss or frequent disconnections. Intermittent issues suggest a physical layer problem preventing a consistent link at the negotiated speed, not a fixed speed setting.

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