call quality; speech quality
Technical term used in telecommunications to describe the clarity and reliability of voice transmission during a phone or VoIP call.
This app has good call quality, so I can talk clearly even with family far away.
We need to review the communication environment to improve call quality.
音質 refers to sound quality in general (music, audio), while 通話品質 specifically refers to the quality of voice transmission in a telephone or VoIP call.
通信品質 is a broader term for communication quality (including data), whereas 通話品質 is limited to voice call quality.
Compound of 通話 (つうわ, 'telephone call') and 品質 (ひんしつ, 'quality').