Carriers say HD Voice calls will be the best yet

Both SK Telecom and KT, the only two carriers selling iPhone 5 in Korea, said yesterday they will make it possible for users of the latest Apple handset to make crystal-clear voice calls dubbed “HD Voice” by expanding the bandwidth, starting today.

The HD Voice wideband audio service on 3G networks enables higher-quality calls similar to VoLTE HD Voice on faster long-term evolution (LTE) networks, the carriers claim. Both companies are launching the new service at the same time.

SK Telecom said it will begin rolling it out in Bundang, Gyeonggi, today and expand it nationwide by the middle of next month.

KT plans to do the same after providing the service in the Suji and Giheung Districts of Yongin, also in Gyeonggi. It will also run a test event for 4,000 college students and office workers in the area before expanding the network across the country, it added.

KT tested the service last month and is now ready to commercialize HD Voice calls on 3G networks, it said.

Wideband audio and VoLTE use the same encoding program, called AMR-WB, which allows for a bandwidth that is 2.2 times larger to facilitate calls that more closely replicate the speaker’s original voice, the carriers claim.

To access the wideband audio service, both users must have the AMR-WB codec on their respective handsets. They must also subscribe to the same carrier as SKT and KT have not yet resolved compatibility issues.

All 3G and 4G LTE smartphones released after Samsung’s Galaxy S3 LTE last year have the codec installed, including the Sony Ericsson XPERIA Arc and Ray.

The number of iPhone 5 users only stood at 500,000 as of early this month, much lower than the 1 million expected by the two carries. The industry interpreted that yesterday’s measure came to boost sales of the Apple phone, which was first released in the domestic market on Dec. 7.

By Kim Jung-yoon [kjy@joongang.co.kr]