[brontitall]

Only if their modem didn’t implement the Hayes command set properly or you could otherwise control the per-character timing of the OS sending. It required a pause (1sec by default), “+++” with no pauses, another pause, _then_ the ATH command

[NitpickLawyer]

I had an external USRobotics 56k modem, I was immune. But the many many "bulk" no-name modems were vulnerable. You could ping entire ranges of dial-up IPs and watch the results on big IRC channels. Uhmmm, allegedly :)

[wat10000]

Which was fairly common, as Hayes had a patent on those pauses.

[brontitall]

Huh, TIL. I guess they might have used TIES

https://en.wikipedia.org/wiki/Time_Independent_Escape_Sequen...

[mycall]

Commas provided 2 second pauses

[brontitall]

Only in the dial string to ATD, surely?