One aspect provides a modem for use at a terminal. The modem comprises a first interface and a processing unit. The first interface is arranged to connect to a communications network. The processing unit is arranged to receive a message from the communications network via the first interface while in an operating mode. The processing unit is also arranged to assess the message on receipt to determine that one or more public warning message is to be broadcast to the modem from the communication network in a second later time period. The processing unit is also arranged to, based on the determination, modify operation of the modem in the second later time period to ensure the one or more public warning message is received and acted on by the modem.