ADTRAN 4200659L1 - Manual (Page 125)

Chapter 6. Diagnostics
61200659L1-1 MX2800 STS-1 User Manual 6-3
Figure 6-3. Tributary Loopback Test
Analog Network
An A NALOG N ETWORK loopback test loops the selected T1/E1 back
to the network (STS-1). The T1/E1 is completely de-multiplexed,
looped back at the T1/E1 line interface unit (LIU) through the LIU
drivers and receivers, and multiplexed back onto the STS-1
network stream. See Figure 6-4 for an illustration of this test.
Figure 6-4. Analog Network 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)
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)