psf21911 ETC-unknow, psf21911 Datasheet - Page 71

• Manufacturer Part Number: psf21911
• Description: Isdn Echocancellation Circuit Terminal Applications Iec-q
• Manufacturer: ETC-unknow

acknowledged, the IOM-clocks are turned off. No signal is sent on the U-interface.
The U-transceiver waits for a wake-up signal TL from the LT-side to start an activation
procedure. To enter state ’IOM Awake’ a wake-up signal (DIN = 0) is required if the IOM-
clocks are disabled. The wake-up signal is provided via the IOM-2 interface (pin DIN =
0). If the IOM-clocks were 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.
EQ-Training
The receiver waits for signal SL1 or SL2 to be able to update the AGC, to recover the
timing phase, to detect the synch-word (SW), and to update the EQ-coefficients. The
“EQ-training” state is left upon detection of binary “0s” in the B- and D-channels for a
period of 6–12 ms corresponding to the detection of SL2.
Error S/T
Loss of framing or loss of incoming signal has been detected on the S/T-interface (EI1).
The LT-side is informed by setting the ACT-bit to “0” (loss of transparency on the NT-
side). The following codes are issued on the C/I-channel:
– Normal activation or single-channel loop-back:
– Loop-back 2:
IOM
Timing signals are delivered on the IOM-2 interface. The U-transceiver enters the
“Deactivated” state again upon detection of the C/I-channel code DI (idle code).
Semiconductor Group
®
-2 Awaked
71
AR
ARL
U-Transceiver
PSB 21911
PSF 21911
11.97