Alcatel 1660SM Technical Handbook page 437

– E bit insertion (E): the outgoing E bit is set to 0 when
•
a failure condition (FC
•
errors (ERR
U
•
the E insertion may be inhibited from controller, in this case E=1.
•
E=1 in other cases.
– A bit insertion (A): the outgoing A bit is set to
•
'0' when a failure condition (FC
•
'1' when Loopback2 (LB
•
passed transparently in other cases;
•
the A bit may be forced from controller.
•
set to '1' (*) when a failure condition (FC
N.B. (*): this option is enabled only in case of Leased Line applications;
– Sa5, Sa6 Messages:
•
the outgoing Sa6 message is inserted in 4 Sa6 bits of 4 consecutive frames, with the following
significance (listed in order of their priority/severity):
– 1000 ––> power fail
– 1111 ––> SSF or AUXP
– 1110 ––> LOF
– 1100 ––> FC
– 0000 ––> loopback2 (LB2) activated
– 0001 ––> alarm REI
– 0010 ––> CRC–4 errors (ERR
– 0011 ––> simultaneous occurrence of both previous (REI
– 0011 ––> only basic–frame alignment on SY2Min signal, when in automatic search
– 0000 ––> normal operations.
•
the outgoing Sa5 bit is set to:
– '0' ––> when loopback2 (LB2) is activated
– '1' ––> in other cases.
– CRC–4 bits insertion: the CRC–4 on data is performed and the result is inserted on bits C1 to C4,
according to G.706.
– Frame Word insertion (FW): the basic–frame and multi–frame alignment words are inserted on the
frame.
– Substituted Frames insertion: the substituted frames are inserted, in case of occurrence of a failure
condition (FC ) on incoming signal from user.
2M
N.B. Substituted frame is a frame with Sa4, Sa5, Sa7, Sa8 as well as all the bits in time slots
1 to 31 set to '1', and with A bit set to '0'.
DOWNSTREAM DIRECTION
(from SDH network to user: incoming signal UP2Min, outgoing signal SY2Mout)
– Loopback–RX: by means of command LB–RX, sent by the controller; this command sends back to
the source the downstream signal.
– AIS Detection: the AIS alarm (AIS
3 zeroes.
– AUXP Detection: the AUXP
...010101... with less than 3 deviation from the pattern itself. It can be enabled from the controller.
– Frame Alignment (FA): it performs basic–frame and multi–frame alignment according to ITU–T
G.706, presettable from the controller (commands BF and MF); the LOF
of non alignment.
ED
02
) is detected on signal from SDH network (UP2Min);
U
) are detected on data from SDH network (UP2Min);
) is detected on signal from user (SY2Min);
2M
) is activated;
2
/AIS on signal from SDH network (UP2Min);
U U
on signal from SDH network (UP2Min);
U
on signal from user (SY2Min);
2M
from user
2M
) from user
2M
) is detected after the reception of 512 bits containing less than
U
alarm is detected after the reception of 512 bits containing the pattern
U
) is detected on signal from SDH network (UP2Min);
U
and ERR
2M
3AL 91669 AA AA
674
)
2M
alarm is declared in case
U
435 / 674