toll quality A voice call having quality comparable to that of an ordinary long distance call, originally placed over the analog circuit-switched public switched telephone network (PSTN). More recently, the quality measurement technique applied to evaluate various implementations of voice encoding techniques, such as pulse code modulation (PCM). In quantitative terms, a voice connection rated as having a mean 74570c20.qxd 9/12/07 12:44 AM Page 493 |