
PEB 80900
Part II
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IEC-T
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: Operational Description
Data Sheet
130
2001-04-02
INFO U2
The LT (and LT-RP, if the NT-RP is synchronized) sends INFO U2 to
enable the own echocanceller to adapt the coefficients, and with the
barker code the NT at the other end is enabled to synchronize. The M
channel on Uk0 may be used to transfer loop commands. Recognizing
INFO U2 is used as a criterion for synchronization.
While the NTC-T AM with IEC-T functionality selected in NT-RP mode
is synchronizing on the received signal, the NTC-T AM with IEC-T
functionality selected in LT-RP mode sends out INFO U2A to enable its
echocanceller to adapt the coefficients, but sending no barker code it
inhibits the NT (-TE, -PABX) to synchronize on the still asynchronous
signal. Due to proceeding synchronization, the Uk0 frame may jump
from time to time. INFO U2A can
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t be detected in the NTC-T AM with
IEC-T functionality selected in NT mode at the far end.
While the NTC-T AM with IEC-T functionality selected (in all NT modes)
is synchronizing on the received signal, it sends out INFO U1A to
enable its echocanceller to adapt the coefficients, but sending no
barker code it inhibits the LT (-RP) to synchronize on the still
asynchronous signal. Due to proceeding synchronization, the Uk0
frame may jump from time to time. INFO U1A can
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t be detected in the
NTC-T AM with IEC-T functionality selected in LT mode at the far end.
When synchronized, the NTC-T AM with IEC-T functionality selected
(in all NT modes) sends the barker code and the LT(-RP) may
synchronize itself. INFO U1 indicates additionally that a terminal
equipment hasn
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t yet activated. When receiving INFO U1, the NTC-T
AM with IEC-T functionality selected indicates the synchronized state
with RDS to layer 2. Usually during activation, no INFO U1 is detected
in the LT because the TE is activated first and INFO U1 changes to
INFO U3 before being detected. The M channel on Uk0 may be used
to transfer code error indications and 1 kbit/s transparent data.
When detecting INFO U3, the NTC-T AM with IEC-T functionality
selected in LT mode in the exchange is allowed to command the
transition to the fully transparent state, because it indicates that the
whole link to the TE is synchronous In both directions. The M channel
on Uk0 may be used to transfer code error indications and 1 kbit/s
transparent data.
The NTC-T AM with IEC-T functionality selected sends periodically
single pulses spaced 1 ms to the Uk0 interface to ensure that it is within
the specified pulse mask.
INFO U2A
INFO U1A
INFO U1
INFO U3
SI