Definity TN-748D

Definity TN748D Tone Detector (TN748D) Provides four touch-tone receivers and two general purpose ton receivers to detect call progress tones, modem answer-back times, transmission test tones, and noise. Provides dial tone detection required for the Automatic Route Selection (ARS) feature, off-premises (out-of-building) keyboard dialing, and off-premises abbreviated dialing. Replaced by TN2182B Tone-Clock, Tone Detector, and Call Classifier.