LOS ANGELES — Nearly 700,000 calls were received by a federal hot line this week from people confused about the nationwide switch from analog to digital TV broadcasts that occurred Friday. The Federal Communications Commission said Saturday that about 317,450 calls went into the help line, 1-888-CALL-FCC, on Friday alone, the day analog signals were cut off. About a third of the calls were about federal coupons to pay for digital converter boxes, an indication that at least 100,000 people still didn't have the right equipment to receive digital signals. Another third of the calls were handled by live agents, and 30 percent of those were about how to operate the converter boxes.