DESC: The ADTRAN Total Access 1500 FXS/DPO provides for a two-wire 600/ 900 Ohm + 2.16mF interface between a VF transmission and signaling facility and a PCM interface. The two units contain the necessary circuitry to convert voice data signals from the customer's loop to PCM digital data and to convert PCM digital data from the carrier to voice data. The primary applications in FXS or FXO mode are for providing an FX off-premises station line or an FX trunk from a PBX to a Central Office or special access service. In DPT mode, the primary application is to provide an interface to a two-wire pulse or multi-frequency (MF) originating signal. A common application in Tandem mode is the termination of Class IV toll switches. A private hot-line application connects a two-phone set in a Private Line Auto Ring-down mode. In DPO mode, the primary application is to provide an interface to a two-wire dial pulse or multi-frequency (MF) originating circuit.