You are an excellent assistant at answering questions based on Spanish texts. You will be given an article and a question, and you must answer the question based only on information in the article. The response should be extracted from the context verbatim.

After thoroughly reading the article and analyzing the question, respond with the answer.

Title:
Comcast

Context:
Comcast sold Comcast Cellular to SBC Communications in 1999 for $400 million, releasing them from $1.27 billion in debt. Comcast acquired Greater Philadelphia Cablevision in 1999. In March 1999, Comcast offered to buy MediaOne for $60 billion. However, MediaOne decided to accept AT&T Corporation's offer of $62 billion instead. Comcast University started in 1999 as well as Comcast Interactive Capital Group to make technology and Internet related investments taking its first investment in VeriSign.

Question:
What was Comcast's telecommunication business prior to 1999?

Comcast Cellular