When call-waiting was introduced, it would usually destroy a 1200 or 2400 baud connection. So we would just call people we wanted to knock offline. It was pretty handy when a "big" chat board had 8 whole simultaneous connections and they were all busy.
When running a BBS the first thing you learned was how to add the codes to disable call waiting to your modem INIT string.
Ah, the good 'ol days. I picked up a cheap fax switch so I could share my dorm line with my BBS. Very cheesy british lady answered the phone "This is the Fax Boss answering your call. To send a fax remain silent, otherwise press 2 to connect" or something like that. I only really remember up to "...to send a fax...". Wish I still had that thing, it was awesome at the time. Of course instead of faxes I was receiving BBS callers but it worked perfectly. Confused my parents constantly.
I think they are saying they couldn't connect as all lines were busy, so they would call someone they assumed was connected, causing the other person to drop off and free up a line, and then try and get that free line.
It was specifically the call-waiting beeps that interrupted the modem connection. I recall my 300 baud modem tolerating it, but 12/2400 (and higher) could not recover from the interruption.
You could set how long the modems would wait for reconnect. We had a service that offered free phone calls with 15 seconds interruption for ads now and then. Worked fine for free bbs time if you knew how to set it :)
When call-waiting was introduced, it would usually destroy a 1200 or 2400 baud connection. So we would just call people we wanted to knock offline. It was pretty handy when a "big" chat board had 8 whole simultaneous connections and they were all busy.