The company is asking for changes in their contract including employee contributions to health care. That contract covers the company's division that oversees landlines and Internet networks.
Forty-five thousand workers with the Communications Workers of America and the International Brotherhood of Electrical Workers (IBEW) walked off the job at midnight Saturday.
The workers are telephone and repair technicians and also customer service representatives and operators, based in offices from Massachusetts to Washington, D.C.
It was unclear how the strike will affect calls to and from Southern California.