psf21911 ETC-unknow, psf21911 Datasheet - Page 67

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

DEA
UOA
LOF
LSEC
LSU
LSUE
SFD
FD
Semiconductor Group
DEA-bit received from the LT-side
– DEA = 0 informs the U-transceiver that a deactivation procedure has been
– DEA = 1 reflects the case when DEA = 0 was detected by faults due to e.g.
UOA-bit received from network side
– UOA = 0 informs the U-transceiver that only the U-interface is to be
– UOA = 1 enables the S/T-interface to activate.
Loss of Framing on the U-interface
This condition is fulfilled if framing is lost for 576 ms. 576 ms are the upper
limit. If the correlation between synchronization word and the input signal is not
optimal, LOF may be issued earlier.
Loss of Signal level behind the Echo Canceler
Internal signal which indicates that the echo canceler has converged.
Loss of Signal level on the U-interface
This signal indicates that a loss of signal level for a duration of 3 ms has been
detected on the U-interface. This short response time is relevant in all cases
where the NT waits for a response (no signal level) from the LT-side, i.e. after
a deactivation has been announced (receipt of DEA = 0), after the NT has lost
framing, and after timer T1 has elapsed.
Loss of Signal level on the U-interface
After a loss of signal has been noticed, a 588 ms timer is started. When it has
elapsed, the LSUE-criterion is fulfilled. This long response time (see also LSU)
is valid in all cases where the NT is not prepared to lose signal level i.e. the LT
has stopped transmission because of loss of framing, an unsuccessful
activation, or the transmission line is interrupted.
Note that 588 ms represent a minimum value; the actual loss of signal might
have occurred earlier, e.g. when a long loop is cut at the NT-side and the echo
coefficients need to be readjusted to the new parameters. Only after the
adjusted coefficients cancel the echo completely, the loss of signal is detected
and the timer can be started (if the long loop is cut at the remote end, the
coefficients are still correct and loss of signal will be detected immediately).
Superframe (ISW) Detected on U-interface
Frame (SW) Detected on U-interface
started by the LT-side.
transmission errors and allows the U-transceiver to recover from this
situation (see state ’Pend. Deact. U’).
activated. The S/T-interface must remain deactivated.
67
U-Transceiver
PSB 21911
PSF 21911
11.97