e/Call progress analysis

Information
has gloss	eng: Call Progress Analysis (CPA), also called Call Progress Detection (CPD), is a generic term for signal processing algorithms that operate on audio during call setup. The goal of CPA is to determine the nature of the callee or the outcome of call setup to an external network (traditional or IP). Specifically, when a call or session is being established, the caller or initiator is interested in knowing if someone answered, if the line is busy, etc. When the caller is an automated application, such as an automated dialer or message broadcasting system, CPA algorithms are used to perform the classification automatically.
lexicalization	eng: Call Progress Analysis
instance of	c/Telephony signals