ADTRAN MX2800 - Analog Network; Digital Line;Net; Figure 6-3. Tributary Loopback Test; Figure 6-4. Analog Network Loopback

Chapter 6. Diagnostics
61200290L1-1 MX2800 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 (DS3). 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 DS3 network
stream. See Figure 6-4 for an illustration of this test.
Figure 6-4. Analog Network Loopback
Digital Line/Net
A
D
IGITAL
L
INE
/N
ET
loopback performs a loopback of the selected
T1/E1 in both the network and local loop directions. Both
loopbacks occur at the T1/E1 LIU. The network side loopback
occurs at the edge of the LIU while the T1/E1 loop side loopback
occurs deep into the LIU through the receiver, receive equalizer,
transmit jitter attenuator, and finally, through the T1/E1 transmit
drivers. See Figure 6-5 on page 6-4 for an illustration of this test.
DSX-3
LIU
M23
MUX/DMUX
M12/G.747
MUX/DMUX
(1 of 7)
F
R
A
M
E
R
D
S
2
F
R
A
M
E
R
D
S
3
.... ....
T1/E1 LIU
(1 of 28)
CODEC
(28 of 28)
CODEC
(1 of 28)
T1/E1 LIU
(28 of 28)
DSX-3
LIU
M23
MUX/DMUX
M12/G.747
MUX/DMUX
(1 of 7)
F
R
A
M
E
R
D
S
2
F
R
A
M
E
R
D
S
3
....
T1/E1 LIU
(1 of 28)
CODEC
(28 of 28)
CODEC
(1 of 28)
T1/E1 LIU
(28 of 28)
DSX-3
LIU
M23
MUX/DMUX
M12/G.747
MUX/DMUX
(1 of 7)
F
R
A
M
E
R
D
S
2
F
R
A
M
E
R
D
S
3
.... ....
T1/E1 LIU
(1 of 28)
CODEC
(28 of 28)
CODEC
(1 of 28)
T1/E1 LIU
(28 of 28)
DSX-3
LIU
M23
MUX/DMUX
M12/G.747
MUX/DMUX
(1 of 7)
F
R
A
M
E
R
D
S
2
F
R
A
M
E
R
D
S
3
....
T1/E1 LIU
(1 of 28)
CODEC
(28 of 28)
CODEC
(1 of 28)
T1/E1 LIU
(28 of 28)