ADC HiGain H2TU-C-202 User Manual page 31

LTPH-UM-1208-01
The Test Center transmits a group of 40 TIP bytes to loop down the loopback. It continues to transmit TIP bytes
in multiples of 20 until the TIP bytes are not returned or until about 2 seconds have elapsed. If the bytes are absent,
a successful loopdown is reported; otherwise, a failed loopdown is reported. The loopdown can also be initiated
by depressing the H2TU-R loopback control pushbutton or by any of the standard 3-in-5 loopdown commands.
The implemented detection or release loopback algorithm functions properly in the presence of a 10
rate.
Since the FT1 mode is a combination of both the full T1 and the latching loopback modes, all codes are always
active. Therefore, if a loopback is initiated by a latching sequence, it can be looped down by either a latching or
generic loopback and vice versa. All loopback commands are completely symmetric in the FT1 mode.
If the latching sequence shown in
cleared, and the H2TU-C reverts back to its initial state where it searches for the initial sequence 1.
After a successful latching sequence terminates in a latched loopback state, the state remains until the Disable
command is detected, or until the LBTO option of NONE, 20, 60, or 120 minutes has expired, whichever occurs
first.
The unframed AIS pattern that is normally sent towards the network for a CI LOS fault condition must be replaced
by the new patterns listed in
FT1
Case Option
1 ENA
2 ENA
3 ENA
4 ENA
5 ENA
(a) Don't care bit.
H2TU-C-202 List 7G
Table 13 (page
Table 14 when the FT1 loopback option is selected.
Table 14. Response of H2TU-C and H2TU-R to LOS and AIS
H2TU-C Output Pattern
H2TU-C
Payload
Input Framing
SF SF 01111110
ESF ESF 01111110
LOS/AIS UNFR 01111110
LOS/AIS SF PL
LOS/AIS ESF PL
22) is interrupted for more than 20 minutes, the detection is
H2TU-R
FDL
Input
N/A LOS/AIS
(a)
X LOS/AIS
N/A LOS/AIS
(a)
X SF/PL
(a)
X ESF/PL
June 6, 2003
Provisioning
-3
bit error
H2TU-R
Output Status Screen
AIS RCV
RLOS/RAIS
XMT IDLE
AIS RCV
RLOS/RAIS
XMT IDLE
AIS RCV
RLOS/RAIS
XMT IDLE
AIS RCV LLOS/LAIS
AIS RCV LLOS/LAIS
23