
PEB 80900
Part II
’
IEC-T
’
: Operational Description
Data Sheet
138
2001-04-02
7.5.2
Control of the Analog Loop and Loop Commands on Uk0
The output of the NTC-T AM with IEC-T functionality selected, e.g. infos on Uk0 or C/I
channel contents, usually depends only on the given state of the NTC-T AM with IEC-T
functionality selected control unit. In some states, several outputs are possible
depending on input. If RESQ isn
’
t set to low or TSP isn
’
t set to high, only the control of
loops is state independent and is evaluated from the C/I channel input.
Any other C/I channel input, low at RESQ or high at TSP, causes the analog loop to be
opened and in the LT modes the M symbol to be set to zero.
In the NT modes, the state diagrams specify only ARD and AID, which are groups of C/
I channel codes, to indicate the activated states. Depending on the mode and the last
recognized received loop command, the NTC-T AM with IEC-T functionality selected
decides whether it sends ARN or AR2, AIN or AIL into the C/I channel.
AWR
AWT
FRJ
Awake signal (INFO U1W or U2W) detected.
INFO U1W of U2W has been sent out
Frame jump, detected by receive or transmit buffer, at least one IOM
frame (18 bit) is repeated or omitted caused by receive or transmit buffer
over/underflow
Timer ended, the started timer has run out
INFO U0 detected
INFO U1 detected
INFO U2 detected
INFO U3 detected
INFO U4H detected
TE
U0
U1
U2
U3
U4H
ARL
(in the C/I channel) always causes the analog loop to be closed in all
modes except the Repeater modes. If INFO U2A or U4 is sent, the M
symbol is set to continuous plus polarity in LT-RP.
(in the C/I channel) causes the M symbol continuously to be set to plus
polarity in the LT, and LT-BURST modes, if INFO U2, U4H or U4 is
sent. The analog loop is closed in LT-RP.
(in the C/I channel) causes the M symbol to be set to alternating plus
and zero polarity in all LT modes.
(in the C/I channel) causes the NTC-T AM with IEC-T functionality
selected to close the analog loop in the repeater modes.
AR2
AR4
AIL