General Description
YTD426B is a communication LSI which provides the ISDN subscriber line interface (two-wire metaric time compression multiplexing operation) and the NT side of the ISDN Basic Rate user-network interface function (digital four-wire time-division full-duplex operation). It also provides the electric characteristics conforming to TTC Standard JT-G961 and JT-I430.

FEATUREs
1. Circuit Termination(CT)
   • Conforms to TTC Standard JT-G961 and JT-I430
      - Two-wire metaric time compression multiplexing operation
      - Digital four{wire time{division full{duplex operation
      - Transmission rate at U reference point: 320 kbps, at T reference point: 192 kbps
      - Frame assembling and disassem bling function
      - State transition control
      - Loopback function
      - U reference point driver control
      - T reference point timing control (switch between short passive bus and long passive bus, point{ to{point)
2. Line Termination(LT)
   • Conforms to TTC Standard JT-G961
      - √f equalizer
      - Bridged Tap (BT) equalizer
   • AFE (Analog F ron t End) In terface
      - AGC (Automatic Gain Control)
      - Data interface
3. B channel interface section
   • B channel multiplexing circuit (LSI external clock 128k to 2,048 kHz)
   • B channel connection/switching function
   • Loopback function
4. Other
• Master/Slave function
   - Ability to control a circuit without the D channel (call origination, B channel control, loopback control)
• CMOS tec hnology
• 144-pin SQFP
• Single +5V supply