INTRODUCTION
The MC145574 is Motorola’s second generation S/T transceiver and is a follow–up to the MC145474/75 transceiver.
The MC145574 provides the improved interfacing capabilities and reduced power consumption required by today’s ISDN applications, while maintaining the functionality and extended range perfor mance of the MC145474/75.
The MC145574 provides an economical VLSI layer 1 interface for the transportation of two 64 kbps B channels and one 16 kbps D channel between the network termination (NT) and terminal equipment applications (TEs). The MC145574 conforms to CCITT I.430, ETSI ETS 300012, and ANSI T1.605 specifications.
The MC145574 provides the modulation/line drive and demodulation/line receive functions required of the interface. In addition, the MC145574 provides the activation/deactivation, error monitoring, fram ing, bit, and octet timing. The MC145574 provides the control signals for the interface to the layer 2 devices. Complete multiframe capability is provided.

 
FEATURES
The features of the MC145574 are described below.
• Conforms to CCITT I.430, ETSI ETS 300012, and ANSI T1.605 Specifications
• Register Compatible With the First Generation MC145474/75
• Exceeds Q.502 Jitter Requirements for TE Slave Applications
• Pin Selectable NT or TE Modes of Operation
• Incorporates the IDL2, With Timeslot Assigner
• Industry Standard Microprocessor SCP
• GCI Interface
• Uses 2.5:1 Transformers for Transmit and Receive
• Exceeds the Recommended Range of Operation in All Configurations
• Complete Multiframing Capability Supported (SC1 – SC5 and Q Channel)
• Optional B Channel Idle, Invert, or Exchange
• Supports Full Range of S/T and IDL2 Loopbacks
• Supports Transmit Power–Down, Listening, and Absolute Minimum Power Modes
• Supports Crystal or External Clock Input Mode
• NT Star and NT Terminal Modes Supported
• Low Power Consumption
• Compatible with 3 V Devices