will offer digital TV service trials that include the HDTV (high-definition TV) format later this year, while NBC
has decided its initial digital TV broadcasts will feature a lower-resolution signal.
MCI is demonstrating its digital capabilities at the National Association of Broadcasters convention in Las Vegas, the company said in a statement. NBC began testing MCI's digital service with the live broadcast of a major league baseball game earlier this month, according to MCI.
NBC will begin a 480 progressive (480p) digital signal, slowly moving up to a 1080 interlaced (1080i) signal to the stations its owns and to its affiliates. 1080i is the highest resolution for HDTV, although the progressive scan technology is considered more advanced.
Neither company indicated whether it expects digital TV viewers to use PCs or TVs. PC systems with enhanced components for viewing HDTV are now beginning to come to the market, offering a challenge to traditional home electronics devices.
"NBC's decision to provide the 1080 interlace format further demonstrates our commitment to providing the highest-quality digital picture to the largest available viewing audience," said Scott Sassa, president of NBC Television Stations.
The broadcast networks have been under pressure from Washington to provide HDTV. Regulators have mandated that broadcasters in the top ten U.S. markets transmit digital broadcasts by November.
Reuters contributed to this report.