has a link to the Adobe Connect 9 Telephone Adapter Development API but it's just a link to the help docs. Where is the link to download the associated SDK code?
I don't believe there is an SDK for this. Just API functionality for integrating a telephone conference system into Connect.
I too believe that what you are trying to accomplish does not need an SDK. The API calls will suffice and as Jorma pointed out, there is no separate SDK for that.
In any case, a comprehensive list of all Adobe Connect documents (except the knowledge base articles) are published at http://helpx.adobe.com/adobe-connect/documentation.html.
We may be wrong in assuming this. Please correct us or ask for more help, if required.