Which technology uses regular phone lines and transmits at speeds up to 256 kbps?

I am completely sure that technology which uses regular phone lines and transmits at speeds up to 256 kbps is called Integrated Services Digital Networks or ISDN which are faster than dial up connection and allows to use a telephone line simultaneously. It's the first fixed broadband wireless connection 

Broadband refers to a high-speed Internet transmission (usually 256Kbps and above) featuring a permanent connection. The most common ways of getting online with broadband are via your TV cable box, your satellite or via your phone line. Cable TV is an easy option, but the most common type of broadband access is through an upgraded home telephone line called ADSL (Asymmetrical Digital Subscriber Line). ADSL is always connected so needn't be dialed up each time, and you can make phone calls on the same line while it's being used.

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