PEF2091 Siemens Semiconductor Group, PEF2091 Datasheet - Page 109

• Manufacturer Part Number: PEF2091
• Description: ICs for Communications(ISDN Echocancellation Circuit)
• Manufacturer: Siemens Semiconductor Group

Data Access in LT Mode
In LT modes (see "Setting Operating Modes", page 50) transparent data access is
available in both directions in the states:
i.e. when the IEC-Q issues the signal SL3T on U, and the Receiver is synchronized (see
"State Transition Diagram in LT Modes", page 147). In these states data from upstream
is handed over via transmit FIFO to the U-Frame in the same order it is received. Data
from downstream is handed over via receive FIFO to the IOM
microprocessor interface (if used) in the same order it is received.
Data Access in NT Mode
In NT modes (see "Setting Operating Modes", page 50) transparent data access will be
available in both directions in the states "Transparent", "Error S/T" and "Pending
Deactivation U", i.e. when the IEC-Q issues the signal SN3T on U (see "State Transition
Diagram in NT, TE and NT-PBX Modes", page 161). If test loop #2 is not closed in the
IEC-Q (see "Test Loop-Backs", page 186) data from downstream is handed over via
transmit FIFO to the U-Frame in the same order it is received. Data from upstream is
handed over via receive FIFO to the IOM
interface (if used) in the same order it is received.
Semiconductor Group
LT
Pending Transparent
Transparent
Pending Deactivation
Line Active
S/T Deactivated
LT-RP
Pending Transparent
Transparent
Pending Deactivation
109
®
-2 interface and to the microprocessor
Operational Description
®
-2 interface and to the
Data Sheet 01.99
PEB 2091
PEF 2091