YTD428_07 Datasheet, PDF (4/28 Pages) YAMAHA CORPORATION – IDSU ISDN DSU for Terminal Equipment

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INTRODUCTION
1. INTRODUCTION
YTD428 is a LSI which provides the ISDN subscriber interface (two-wire 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 is capable of providing the electric
characteristics conforming to TTC Standard JT-I430 and JT-G961.
YTD428 incorporates the circuit termination and line termination functions on a single chip
allowing the user to easily configure a DSU (Digital Service Unit) that consumes small amount of
power at a minimal cost.
In addition, a TTL interface is provided at the T reference point (layer 1 level). This feature is
especially effective when combined with YAMAHA's ISDN LSI for S/T reference point interface,
YTD423 or YTD418. It allows considerable cost reduction on parts around the pulse transformer
when constructing a device with a built-in DSU.
The driver/receiver section of the T reference point interface can be separated from the DSU section
and be used independently. The user can enable or disable this feature as necessary.