
PEB 80900
Part II
’
IEC-T
’
: Operational Description
Data Sheet
141
2001-04-02
Link to TE synch.
The NTC-T AM with IEC-T functionality selected in LT mode in
the exchange has received INFO U3 indicating that the link is
synchronized from and to the TE. The NTC-T AM with IEC-T
functionality selected in LT mode commands, with 1 ms INFO
U4H, the whole link to the TE to be switched transparent. The
RDS counter and the adaption of receiver coefficients are
enabled. 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.
After being synchronized itself and indicating this with ARN/
AR2, the NTC-T AM with IEC-T functionality selected in NT-RP
mode waits for the message AIU from the LT-RP indicating that
it also is synchronized. The NT-RP sends transparently on Uk0
the received data from LT-RP. Because the LT-RP issues only
the AIU C/I-code when it has detected INFO U1 or U3, it is
ensured that the NT-RP did not send out INFO U1 or U3 itself
until the LT-RP is synchronized.
With a low on pin CLS in LT modes, RES, SSP or LTD In the CA
channel or with a low on pin RESQ as well as a high on pin TSP,
the NTC-T AM with IEC-T functionality selected goes to the
maintenance state. The user data (B+B+D) on pin DOUT is
clamped to high (except repeater modes).
If the NTC-T AM with IEC-T functionality selected in LT mode
detects a high on pin CLS indicating
“
Power feed off
”
it puts in
this state code HI in the C/I channel, otherwise DA.
If pins TSP and RESQ are high or code SSP is in the C/I channel
input, the NTC-T AM with IEC-T functionality selected sends
each ms a single pulse on the line to enable the test whether it
fits into the specified pulse mask.
Detecting LTD in the C/I channel is the only possibility for the
NTC-T AM with IEC-T functionality selected in LT mode to set
output pin DISS high.
IF pins RESQ and TSP are low or RES is in the C/I channel
input, the NTC-T AM with IEC-T functionality selected is reset in
this state erasing all stored coefficients. If RESQ pin is low,
DISS pin is set to high. If the reset is given only in the C/I
channel, DISS-pin is set to low.
In the LT mode, the NTC-T AM with IEC-T functionality selected
leaves the maintenance state only if CLS and TSP are low, RSQ
is high and code DR or ARL is in the C/I channel.
LT-RP Synchronizing
Maintenance state