While replacing corrupted firmware on a headless rack server, a technician must follow the vendor's instructions: "Connect a laptop to the system board's DB-9 serial port using an RS-232 null-modem cable at 115 200 8-N-1." The laptop has only USB ports, and no additional active devices or network connections can be introduced at the rack. Which cabling solution will enable the console session?
A USB-to-RS-232 adapter on the laptop connected to a female-to-female DB-9 null-modem cable
A straight-through DB-9 male-to-female cable attached to a USB-to-Ethernet adapter
A KVM-over-IP dongle that bridges the server's video and USB ports to the data-center LAN
A flat blue RJ-45 rollover console cable with a USB-to-RJ-45 adapter
The instructions require an RS-232 null-modem connection, which crosses the transmit and receive lines so two DTE devices (the laptop and the server) can communicate. Because the laptop lacks a native serial interface, it first needs a USB-to-RS-232 adapter to provide the correct signaling level. Attaching a female-to-female DB-9 null-modem cable to that adapter completes the required crossover, letting the terminal program communicate at 115 200 8-N-1. A flat RJ-45 rollover cable fits network-equipment console ports, not a DB-9 connector. A straight-through DB-9 cable leaves TX and RX uncrossed, so two DTE ports cannot talk. A KVM-over-IP dongle is an active device that also adds network infrastructure, violating the constraint of no extra powered hardware or network links.
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