The Definity TN748C features:

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

2 Year Warranty