Simply put, our 6 foot, Cisco compatible Blue RJ45 to DB9 Rollover Console Cables (or management cable) are null-modem cables that allow users the ability to communicate and configure a networking device. These particular null modem cables are "rolled over" meaning that on connector A pin 1 connects to pin 8 on connector B, pin 2 to pin 7 respectively, and so on. The wiring is exactly the opposite on one connector as it is on the other. This wiring allows users to configure various network devices by attaching the DB9 female portion of the cord to the serial port on your computer, and the RJ45 plug into the device (router, firewall, switch, etc.). Why make the switch? This type of one-piece cable replaces older "kits" that contained multiple cables and adapters.