PEF2091 Siemens Semiconductor Group, PEF2091 Datasheet - Page 169

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

Alerting 1
"Alerting 1" state is entered when a wake-up tone was received in the "Receive Reset"
state and the deactivation procedure on the NT side was not yet finished. The
transmission of wake-up tone TN is started.
Analog Loop-Back
Upon detection of binary "1s" for a period of 6–12 ms and of the superframe indication,
the "Analog loop-back" state is entered and transparency is achieved in both directions
of transmission. This state can be left by making use of any unconditional command.
Only the C/I-channel code RES should be used, however. This assures that the EC- and
EQ-coefficients are set to zero and that for a subsequent normal activation procedure
the Receiver updating algorithms converge correctly.
Deactivated
The ’Deactivated’ state is a power-down state. If there are no pending Monitor Channel
messages from the IEC-Q, i.e. all Monitor Channel messages have been acknowledged,
the IOM
The IEC-Q waits for a wake-up signal TL from the LT side to start an activation
procedure. To enter state ’IOM
mode) is required if the IOM
the IOM
active in state ’Deactivated’ C/I-code TIM is sufficient for a transition to state ’IOM
Awake’.
EC Training
The signal SN1 is transmitted on the U-interface to allow the NT Receiver to update the
EC-coefficients. The automatic gain control (AGC), the timing recovery and the EQ
updating algorithm are disabled. The "EC-training" state is left when the EC has
converged (LSEC) or when timer T12 has elapsed.
EC-Training 1
The "EC-Training 1" state is entered if transmission of signal SN1 has to be started and
the deactivation procedure on the NT side is not yet finished.
EC-Training AL
This state is entered in the case of an analog loop-back. The signal SN1 is transmitted
on the U-interface to allow the NT Receiver to update the EC-coefficients. The automatic
gain control (AGC), the timing recovery and the EQ updating algorithm are disabled. The
"EC-training" state is left when the EC has converged (LSEC) or when timer T12 has
elapsed.
Semiconductor Group
®
®
-2-clocks are turned off. No signal is sent on the U-interface.
-2 interface (pin DIN = 0 or bit SPU=0 in µP mode). If the IOM
®
-2-clocks are disabled. The wake-up signal is provided via
®
-2 Awake’ a wake-up signal (DIN = 0 or SPU=0 in µP
169
Operational Description
®
Data Sheet 01.99
-2-clocks were
PEB 2091
PEF 2091
®
-2