YTD439 Datasheet, PDF (2/15 Pages) List of Unclassifed Manufacturers – ISDN BRI controller for Terminal Equipment with built-in DSU

Layer 1 control block
• Frame assembling and disassembling function.
• I430 TTL output pin
Layer 2 control block
• Built-in LAPD protocol (supports four links).
• Call control and D-channel packet function.
Layer 3 interface block
• Message exchange through I/O access (large 1088-byte FIFO).
B channel HDLC controller
• Supports CRC-CCITT and CRC-32.
• 128k/64k/56k rate adaption
B channel transparent
• Supports PIAFS 64k/32k.
• Flexible rate adaption function.
B channel DATA FIFO
• Transmission and reception: 128-byte FIFO × 2 channels.
TD switch
• Switch circuit for 8 channels of B channel data.
• 512 k to 2,048 kHz PCM highway.
Others
• Terminal block can be disconnected. Power can be cut off.
• Terminal block sleep mode.
• Power supply to the analog block: +5 V.
Power supply to the digital block: +5 V or 3.3 V.
• 5 V tolerant I/O pin
• 100-pin SQFP.
❍ Applications
• Terminal adapter
• Remote router
• ISDN telephone
• ISDN home telephone
• ISDN Facsimile
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