Disable call waiting for dialup modem?

Infopackets Reader Joel M. writes:

" Hello Dennis,

This is my first time to write to you because I have usually found the answers to my questions in your wonderful articles. Please keep them coming!

I do not have the call waiting feature disabled on my computer, nor do I have one of those 'catch-a-call' boxes which allows me to answer an incoming call when I'm connected to the Internet. Instead, I gone to Control Panel -> Modems -> Advanced Settings, and used the modem command 'ATS11=254' which (I believe) has given me the option of ignoring / allow incoming calls. Unfortunately, a few days ago, this procedure stopped working.

Do you have any suggestions that I can try? I am a newbie at this and am sorry that this is so long, but I could sure use some help on this as it worked great for a long time. "

My response:

As far as I understand, the S11 registry is responsible for setting the dial speed. I have used S11=40 in the past when setting up friend's PCs and it has proven to work fairly well. To ignore call waiting, you will need to have the modem dial *70 before you're ISP's phone number.

Most phone companies have reserved the dialing prefix *70 which disables call waiting. Unfortunately, I don't know where the dial prefix is located in the Control Panel off hand because I don't have a modem installed in my computer.

Side note: If the modem does not dial correctly because you need a longer pause between *70 and the ISP's phone number, simply add more commas to the phone number string. For example, if your ISP phone # is 555-1234, you can edit the number to look like: *70,,,555-1234.

And for your modem initialization string, try using: ATL3M1S11=40. To break it down, L3 = modem speaker LOUD (L1 = soft, L2 = louder, L3 loudest), M1 = modem speaker ON, and S11=40 = dialing speed. In this case, S11=40 should dial fairly quickly. If you decide to use S11=40 and the modem is dialing too fast, increase the value to 45 or 50 (and so on).