Provisioning
61180105L1-5C
9
Options
Select
the
appropriate
Option
and
Rate
using
circuit
board
switches
SW1
and
SW4
as
illustrated
in
.
Select
options
prior
to
board
insertion.
Figure 2. Option and Rate Selection Switches
Protected Loopback (PLB)
ADTRAN’s
Protected
Loopback
supports
the
new
proposed
DDS
latching
loopback
standard
in
T1E1.2/99
‐
007R1.
When
Protected
Loopback
is
enabled,
the
TR
DDS
‐
DP
will
respond
to
latching
loopback
when
the
idle
code
preamble
is
sent
prior
to
the
latching
loopback
sequence
specified
in
TR62310
and
ANSI
T1.107.
Protected
Loopback
prevents
false
latching
loopbacks
when
the
loopback
sequence
is
embedded
in
customer
payload
data.
Test
equipment
should
support
T1E1.2/99
‐
007R1
to
perform
testing
at
64
kbps
when
protected
loopback
is
enabled.
See
for
the
latching
loopback
sequence
requirement
when
Protected
Loopback
is
enabled.
Table 6. Protected Loopback Mode Requirement
Sequence Function
Byte Code
# of Received Bytes
Exit
Data
Protocol
Idle
‐
11111110
Minimum
of
35
Idle
bytes
Clear
existing
loopbacks
Transition
in
progress
(TIP)
X0111010
Minimum
of
35
TIP
bytes
Identify
device
to
be
looped
Loopback
select
code
(LSC)
X0000101
‐
DS0
X1010101
‐
OCU
X0110001
‐
CSU
X1000001
‐
NIE
Minimum
of
35
LSC
bytes
Prepare
to
loop;
send
MAP
code
after
30
bytes
Loopback
enabled
(LBE)
X1010110
Minimum
of
100
LBE
bytes
Activate
loopback
Far
‐
End
voice
(FEV)
X1011010
Minimum
of
32
FEV
bytes
1
1
1
O
N
O
N
O
N
2
2
2
3
3
3
4
4
4
5
5
5
6
6
6
7
7
7
8
8
8
1
1
1
O
N
O
N
O
N
2
2
2
3
3
3
4
4
4
5
5
5
