Справочник Пользователя для Adtran 1200291L1
Chapter 6. Diagnostics
6-10
MX2800 STS-1 User Manual
61200659L1-1
Digital Loopback
A
D
IGITAL
L
OOPBACK
loops the entire STS-1 back to the local loop
side. The end effect of this test is a loopback of all VT/Ports after
passing through the STS-1 mapper and partially through the LIU.
The incoming STS-1 data is ignored and the outgoing STS-1 stream
is substituted in its place just prior to entering the STS-1 encoder
block of the LIU. This data will be processed through the “Transmit
Clock Duty Cycle Adjust” PLL and the “HDB3/B3ZS Encoder”
block. At this point, the data will be looped back to the “HDB3/
B3ZS Encoder” block. This test is illustrated in Figure 6-13.
passing through the STS-1 mapper and partially through the LIU.
The incoming STS-1 data is ignored and the outgoing STS-1 stream
is substituted in its place just prior to entering the STS-1 encoder
block of the LIU. This data will be processed through the “Transmit
Clock Duty Cycle Adjust” PLL and the “HDB3/B3ZS Encoder”
block. At this point, the data will be looped back to the “HDB3/
B3ZS Encoder” block. This test is illustrated in Figure 6-13.
Figure 6-13. Digital Loopback
STS-1
MAPPER
T1/E1 LIU
(1 of 28)
T1/E1 LIU
(28 of 28)
STS-1
LIU
CODEC
(1 of 28)
CODEC
(28 of 28)