
PEB 80900
Part II
’
IEC-T
’
: Operational Description
Data Sheet
143
2001-04-02
Uk0 synch. no TE
The NTC-T AM with IEC-T functionality selected in LT mode in
the exchange has recognized INFO U1, so 1152 subsequent
bits have been transferred without any bit error. This is an
indication for synchronization of Uk0, but no terminal equipment
has announced its presence yet. The NTC-T AM with IEC-T
functionality selected is now ready to go to the transparent state,
if a TE was connected. From this state of activation, the RDS
counter and the adaption of receiver coefficients are enabled
until deactivation is performed.
In case of an analog loop, the NTC-T AM with IEC-T
functionality selected leaves this state again at once. If no loop
should be closed, the NTC-T AM with IEC-T functionality
selected waits for INFO U3 indicating that at least one TE is at
the end of the link or for deactivation. If in 64 subsequent Uk0
frames the Barker-code is not found at the expected position,
the NTC-T AM with IEC-T functionality selected gives out RSYD
or RSYU on the C/I channel until it has resynchronized finding
the Barker-code on the same position in 4 subsequent frames.
In this state, the NTC-T AM with IEC-T functionality selected in
all NT modes is synchronized. It has received the information
that the associated downstream device is synchronized itself,
and it waits now for the permission to go to the transparent state.
The user data (B+B+D) on pin DOUT is clamped to high (except
NT-RP).
Before indicating to the layer 2 device that the transparent state
has been reached, the NTC-T AM with IEC-T functionality
selected in LT mode in the exchange waits 1 ms to be sure that
the whole link is already transparent upstream too. The user
data (B+B+D) on pin DOUT is clamped to high (except repeater
modes). If in 64 subsequent Uk0 frames the Barker-code is not
found at the expected position, the NTC-T AM with IEC-T
functionality selected gives out RSYD or RSYU on the C/I
channel until it has resynchronized finding the Barker-code on
the same position in 4 subsequent frames.
Wait for INFO U4H
Wait 1 ms