Abstract: A communication system includes a network control facility (205), two downstream channels (212, 213), at least one remote interface unit (209, 210), and at least one communication device (201, 202) associated with each remote interface unit (RIU). Each RIU operates in one of two operating modes: a low power, standby mode and a high power, active mode. One downstream channel (212) is the primary downstream channel and is used by the network control facility to communicate user information and normal maintenance or control information to the RIU when the RIU is in the active mode. The other downstream channel (213) is the secondary downstream channel and is used by the network control facility to communicate special control information, such as a wake-up command, to the RIU when the RIU is in standby mode. The wake-up command instructs the RIU to transition from standby mode to active mode in order to receive user or control information over the primary downstream channel.