The purpose of this study is to verify the impact of a deterioration of the sound quality of voice by a telephone line on estimating Vitality as the extent of depressive tendency based on voice analysis using MIMOSYS. First, the voices of about 1,000 people recorded using a recorder were prepared. Next, each voice was coded and resampled in preparation for transmission over a phone line. Vitalities obtained by analyzing the voices before and after these processes were compared. The results showed high correlation between the Vitality after coding and Vitality before coding, revealing that using a telephone would be an effective way to obtain voices.