Some unnamed ISPs added the *70 or such call waiting disable to their dial up strings because of users that couldn't do that or calls to the support lines about dropped calls. I leave it to you to research that issue.
Another nutty one is the old "it worked before" issue. "Tech" runs into that and there is no cure for those owners. Even when Tech shows them it working with a new modem they won't accept that old paint has stopped performing it's old tricks. No fix for those I fear. But it makes for good income for Tech since he charges for the call in spite of the owner thinking their old modem should still work.
Sorry, no real cures to be had for free for some but I hope this gets you thinking along new lines.
I have call waiting on my phone so that my dial-up internet connection will disconnect for incoming calls, right? It has always worked on other phone lines I have, but for some reason on a new line it has NOT kicked me off internet when call comes in. When someone calls while I'm on the internet, they say the line just rings and rings. I get no indication (on my end) that there is a call coming in- no ring or no disconnection from internet. Could the problem be with my computer settings if they have changed in any way? Help! If someone can help me navigate my way thru computer settings to get it working to where it disconnects when I get a phone call, I'd welcome and appreciate any suggestions or comments on what I may be able to do.
I have also contacted phone company for their suggestions, but wanted some "techy" info. from experts.