CHANNEL MODE

Usage: MODE <room> +|-<mode(s)>[+|- <mode(s)> [<nickname>|<user@host>]

Sets various options for the room. You must be an operator in the room to issue these commands, some commands are reserved for Server Operators:

A - Auditorium, b - Ban, c - Prevent Colors, d - Nick Change Restriction, e - Prevent CTCPs, i - Invite Only, j - Java Only, k - Keyed, l - Limit, L - Language Filtering, m - Moderated, M - Moderation Forward, n - No External Messages, N - Moderation Receive, o - Channel Operator Status, O - Channel Overflow, p - Private, r - Registered, R - n/a, s - Secret, t - Topic, u - Channel User, v - Voice, w - n/a, y - n/a, z - Encrypt Only

For more information type /hs cmode

Examples:
/hs help cmode <mode>