PEB2085 Datasheet, PDF (174/320 Pages) Siemens Semiconductor Group – ISDN SubscribernAccess Controller

Operational Description
F8 Lost Framing
This is the condition where the ISAC-S has lost frame synchronization and is awaiting re-
synchronization by INFO2 or INFO4 or deactivation by INFO0.
Unconditional States
Loop 3 Closed
On Activate Request Loop command, INFO3 is sent by the line transmitter internally to the line
receiver (INFO0 is transmitted to the line). The receiver is not yet synchronized.
Loop 3 Activated
The receiver is synchronized on INFO3 which is looped back internally from the transmitter.
Data may be sent. The indication "TI" or "ATI" is output depending on whether or not a signal
different from INFO0 is detected on the S interface.
Test Mode Continuous Pulses
Continuous alternating pulses are sent.
Test Mode Single Pulses
Single alternating pulses are sent (2-kHz repetition rate).
Reset State
A software reset (RS) forces the ISAC-S to an idle state where the analog components are
disabled (transmission of INFO0) and the S line awake detector is inactive. Thus activation
from the NT is not possible. Clocks are still supplied (TE mode) and the outputs are in a low
impedance state.
The reset state should be left only with a "Deactivation Indication Upstream" (DIU) command
before any other command is given.
Semiconductor Group
174