3Com 4210 9-Port Configuration Manual page 51

Press... To...
Use the partial online help. That is, when you input an
incomplete keyword and press <Tab>, if the input
parameter uniquely identifies a complete keyword, the
system substitutes the complete keyword for the input
<Tab> parameter; if more than one keywords match the input
parameter, you can display them one by one (in complete
form) by pressing <Tab> repeatedly; if no keyword
matches the input parameter, the system displays your
original input on a new line without any change.
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