For getting online with your DC is easy if you have a telephone line, and a ISP.
A new project for "free" dial-up as emerged and is in http://www.terradialup.com
, so after reading this, you think, well nothing new, dial-up is standard but nowadays is hard to have a real telephone line.
Terradial up also support using your broadband, just use a Voip ata device and link to their servers. This option is really free as you dont have the cost of the call. No need for having your own pc/raspberry server or custom cables.
Here is a example, but instead of a telephone you can link the DC console
Go to their website, request a user and tell your experience, requests can take some time.
The aim is to have a telephone dial-in number all over the world.