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

DSX-3 DSX-3
LIU LIU

Analog Network

An A
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.
DSX-3 DSX-3
LIU LIU

Digital Line/Net

A D
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.
61200290L1-1
F F
M12/G.747 M12/G.747
R R
D D
A A
S S MUX/DMUX MUX/DMUX
F F
M M
2
2
R R
E E
M23 M23
D D
A A
R R
S S
M M MUX/DMUX MUX/DMUX
3 3
E E
R R
N
NALOG ETWORK
F F
M12/G.747 M12/G.747
R R
D D
A A
MUX/DMUX MUX/DMUX
S S
F F
M M
2 2
R R
E E
D D M23 M23
A A
R R
S S
M M
MUX/DMUX MUX/DMUX
3 3
E E
R R
L /N loopback performs a loopback of the selected
IGITAL INE ET
MX2800 User Manual
CODEC CODEC
(1 of 28) (1 of 28)
(1 of 7) (1 of 7)
CODEC CODEC
(28 of 28) (28 of 28)

Figure 6-3. Tributary Loopback Test

loopback test loops the selected T1/E1 back
CODEC CODEC
(1 of 28) (1 of 28)
(1 of 7) (1 of 7)
CODEC CODEC
(28 of 28) (28 of 28)

Figure 6-4. Analog Network Loopback

Chapter 6. Diagnostics
T1/E1 LIU T1/E1 LIU
(1 of 28) (1 of 28)
T1/E1 LIU T1/E1 LIU
(28 of 28) (28 of 28)
T1/E1 LIU T1/E1 LIU
(1 of 28) (1 of 28)
T1/E1 LIU T1/E1 LIU
(28 of 28) (28 of 28)
6-3