Chat scripts are typically used only on dial-up links. Leased-line links do not use chat scripts unless the link includes an asynchronous interface that requires startup configuration.
The contents of the chat script are determined by the requirements of your modem model or ISDN TA, and the remote peer. These contents appear as a set of expect-send strings. The dial-out machine and its remote peers exchange the strings as part of the communications initiation process.
An expect string contains characters that the dial-out host machine expects to receive from the remote peer to initiate conversation. A send string contains characters that the dial-out machine sends to the remote peer after receiving the expect string.
Information in the chat script usually includes the following:
Modem commands, often referred to as AT commands, which enable the modem to transmit data over the telephone
Phone number of the target peer
This phone number might be the number that is required by your ISP, or a dial-in server at a corporate site, or an individual machine.
Time-out value, if required
Login sequence that is expected from the remote peer
Login sequence that is sent by the dial-out machine