what are these messages from the chat script?
 

Hi,
My modem is external USB 2.0 Fax dial up modem, and use the chat script in debian squeeze to connect to my isp, the chat script can establish a connection successfully, i check the connection with:
there are time to time these messages:
i check the chat process with:
Is it normal the chat script should run as a process or close after establish a connection, and what are above messages?

The short version is that they are commands to the modem, more or less derived from the Hayes command set.

http://en.wikipedia.org/wiki/Hayes_command_set

Afterthought: I used to know some of the AT commands by heart back in the BBS days.

thanks for reply, i know these are commands to modem by chat script, but question is why after connection chat should send these commands to modem, and is chat should run after connection established or just should exit?

It's been a long time since I've had to deal with this, but, if I remember, every time you send or receive something across the modem connection, there has to be an accompanying command to the modem so it knows what to do with or in response to the data.

Back to your other question, one would not normally expect a chat session to close spontaneously after the connection is made, but *&^&^$0***$88&^%[NO CARRIER].

In other words, it can happen due to interference, faulty equipment, or other legitimate reasons.

Perhaps someone with more recent experience with AT commands will help us out here.