Manson called people in California, New Jersey and Florida with an LG flip phone found under his prison bunk in March 2009, the Los Angeles Times reported in 2011. A second cellphone was found a year later. Thirty days were added to his sentence for the first offense, officials said.
Earlier, a homemade weapon was found in his possession. A parole board will consider whether Manson should be released from prison on Wednesday, though the chances of that happening are pretty slim. The board has rejected parole for Manson 11 times before.
Manson has informed local prison officials that he will not be at next week's hearing.
Manson and other members of his "family" were convicted of killing pregnant actress Sharon Tate and six other people during a bloody rampage in the Los Angeles area during two August nights in 1969. Tate begged for the life of her child but was stabbed repeatedly in the stomach.
WARNING: GRAPHIC PHOTOS BELOW