PORTLAND, Ore. -- In Portland and across the country, local television stations were turning off their analog transmissions Friday and converting to digital-only signals. KGW-TV switched to all digital transmission at 3 a.m. Friday, and all Portland stations planned to switch by the end of the day. More: Portland switch schedule

According to a Neilsen study, more than 40,000 metro Portland households were not ready for the switch to all-digital TV transmission.

By 10 a.m., KGW's switchboard had received more than 50 calls from viewers having trouble with the digital transition.

An FCC digital transition call center was set up at Oregon Public Broadcasting studios to answer questions concerning the change. At least 10 staffers fielded some 600 calls on Thursday and as many as 1,500 on Friday, all from Portland metro residents who were unsure of "what to do" about their signals.

The top three issues were rescanning televisions, antennae or reception issues, and the government-issued DTV coupons.

Coupons are still available but will take about a week to arrive via U.S. mail.

  Antenna/reception

 Rescanning

 Converter Box Coupons

The Neilsen study found that 3.7 percent of Portland-area households were not ready at all, and another 10.9 percent were only partly ready. Neilsen estimated that as many as 2 million households nationwide were not ready for the switch to digital.

TV sets that haven't been converted to digital will just see "snow" once analog transmission ceases.

Even some viewers with DTV-ready sets will still need to re-scan their TV. Cable and satellite subscribers will not, but those watching TV via an over-the-air signal will need to re-scan their TV. How to re-scan

Two help hotlines were available for those with DTV questions.

Portland's local DTV hotline is: 800-241-8123.

The local hotline number was scheduled to be staffed until 8 p.m.Thursday, on Friday from 7 a.m. to 7 p.m., and on Saturday and Sunday from 8 a.m. to 5 p.m..

The FCC also offered a 24/7 hotline at 1-888-225-5322.

More: DTV Questions & Answers