YTD439 Datasheet, PDF (7/15 Pages) List of Unclassifed Manufacturers – ISDN BRI controller for Terminal Equipment with built-in DSU

❑ Overview of Functions
❍ DSU Block
The DSU section achieves DSU functions of subscriber line interface (two-wire time
compression multiplexing operation) and the user-network interface (digital four-wire time
division full-duplex operation) for ISDN. The electrical characteristics conforming to TTC
Standard JT-G961 is achieved.
Line Termination Block (LT Block)
The line termination section provides the √f equalization that compensates for the line
loss and amplitude distortion and the bridged tap equalization that compensates for
signal distortion.
Circuit Termination Block (CT Block)
The circuit termination provides the following functions:
• U/T reference point rate adaption and frame assembling and disassembling
• State transition control
• U reference point driver circuit control
• T reference point reception timing control
• Loopback control (loopback 2 and loopback C for maintenance and testing)
❍ S/T Reference Point Driver/Receiver Block
By connecting S/T reference point transformers, the electrical characteristics conforming to
TTC Standard JT-I430 is achieved. YTD439 normally operates in the DSU mode. However, if
the DSU function is disconnected, YTD439 switches to the terminal mode and operates as a
S/T reference point terminal LSI.
❍ T Reference Point Connection Control Block
When the DSU block is disconnected or when the driver/receiver functions are disabled, the
input/output signal of JT-I430 is switched within this control block. In addition, when
disconnecting the power to the terminal block or the S/T reference point driver/receiver
block, this block disconnects the signal between the DSU block and the block that is disabled.
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