UPDATE 1-Nippon Telegraph op profit seen falling 15 pct - Nikkei

Nov 7 (Reuters) - Nippon Telegraph and Telephone Corp (9432.T: Quote, Profile, Research) will likely report an operating profit of about 630 billion yen ($7.01 billion) in the April-September half, a drop of 15 percent on the year, the Nikkei business daily said.

Sales are estimated to fall 3 percent to about 5 trillion yen, the Nikkei said without citing sources.

The drop in operating profit stems mainly from the cellular phone service unit NTT DoCoMo Inc (9437.T: Quote, Profile, Research), the daily said, adding that sales fell on lower call revenue and a drop in cellular phone demand.

The company also did not benefit from the introduction of installment sales plans for cell phone handsets, the Nikkei said.

Real estate, financial and other operations were also apparently sluggish, the daily added. ($1=89.83 Yen) (Reporting by Bhaswati Mukhopadhyay in Bangalore; Editing by Ratul Ray Chaudhuri)