3Com 4210 PWR Configuration Manual page 27

Figure 4 Set port parameters
3 Plug in the switch so it has power. You will be prompted to press the Enter key if
the switch successfully completes POST (power-on self test). The prompt (such as
<4210>) appears after you press the Enter key, as shown in Figure 5.
Figure 5 HyperTerminal CLI
4 You can then configure the switch or check the information about the switch by
executing the corresponding commands. You can also acquire help by typing the ?
character.
Logging in through the Console Port 25