[nonamesleft]

Also seemed to work over ICMP ping, with "+++ATH0M0DT112", they did not return to the channel.

I think it was some buggy Rockwell modem chips that did not require the delay between +++ and switching to command mode, but it has been some decades.

[bigfatkitten]

It did indeed, though people used to hide their IP addresses through various means, and so CTCP was usually a sure fire winner.

Most cheap modems seemed to ignore the required 1 second (IIRC) delay. Well-heeled users who could afford U.S. Robotics et al were safe, winmodem users were not.