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.
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.