PEB2080 SIEMENS [Siemens Semiconductor Group], PEB2080 Datasheet - Page 14

• Manufacturer Part Number: PEB2080
• Description: S/T Bus Interface Circuit(SBC)
• Manufacturer: SIEMENS [Siemens Semiconductor Group]

2
The S-bus interface circuit PEx 2080 performs the layer-1 functions for the S/T interface of the ISDN
basic access.
2.1
The common functions for all operating modes are:
Mode specific functions are:
Analog Functions
The full-bauded pseudo-ternary pulse shaping is achieved with the integrated transmitter which is
realized as a current limited voltage source. A voltage of 2.1 V is delivered between SX1-SX2,
which yields a current of 7.5 mA over 280 .
The receiver is designed as a threshold detector with adaptively switched threshold levels. Pin SR1
delivers 2.5 V as an output, which is the virtual ground of the input signal on pin SR2.
An external transformer of ratio 2:1 is needed in both receive and transmit direction to provide for
isolation and transform voltage levels according to CCITT recommendations.
Semiconductor Group
Iine transceiver functions for the S interface according to the electrical specifications of
CCITT I.430;
dynamically adaptive threshold control for the receiver;
conversion of the frame structure between IOM and S interfaces;
conversion from/to binary to/from pseudo-ternary code.
receive timing recovery;
S-timing generation using IOM timing synchronous to system, or vice versa;
D-channel access control and priority handling;
D-channel echo bit generation;
activation/deactivation procedures, triggered by primitives received over the IOM interface or by
INFO’s received from the line;
frame alignment according to CCITT Q.503;
execution of test loops.
Functional Description
General Functions and Device Architecture
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Functional Description