Provisioning LTPH-UM-1049-02, Issue 2

30 January 9, 2002 H2TU-C-319 List 4E

The MTAF IN port of TB6 can connect to an external test facility circuit consisting of an HDSL2 wire line simulator or test pair and a golden H2TU-R remote HDSL2 unit. This connection allows the H2TU-C Unit Under Test (UUT) to be tested from its DSX-1 interface on the simulated test circuit. This allows any problem to be isolated to either the equipment or the facilities. Since this MTA test event disrupts service, it is always accompanied by an MTA/LOSW alarm that is displayed on both the front panel and status screen.Simultaneous access of the MTAF and MTAE backplane buses by more than one H2TU-C would connect two loops and two transceivers together and must be prevented. Such a conflict is inhibited when the shelf is under command of the HMU-319 management unit. However, when the H2TU-Cs are under manual control, the conflict can occur if the MTA command is issued to two line units in the same shelf or in different shelves if the TB3 and TB6 ports are bussed together to create a single test access to an entire bay. Therefore, the user must be aware of this potential conflict and take care to avoid it.Figure10 on page 29 shows a future enhancement of the H2TU-C that uses separate commands to control the two test relays K1 and K2. This allows the IN and OUT ports of TB6 to be connected to each other which creates a circuit that allows a suspected H2TU-C to be replaced by a standby H2TU-C. The MTAF relay K1-D is activated in the defective H2TU-C unit and the MTAE relay K2-S activated in the standby H2TU-C unit. This allows the original facility circuit of the defective H2TU-C to be connected, by way of the TB6 jumpers to the standby H2TU-C unit. The test center can then switch the DSX-1 interface from the defective H2TU-C unit to the standby unit within a DACS or M13 MUX circuit to complete the test circuit.Figure 12. H2TU-C-319 List 4E Block Diagram
7
To external
DSX-1
cross-connect
panel
HMU
M
U
X
O
p
t
I
o
n
User option
H2TU-C-319, L4E
AIS/QRSS
ADS1
Option
control
Micro I/O
T1
Payload
DSX-1 (MUX)
M = MUX or SPTF
A = Auxiliary
C = CTHR (Cut through) or SPTE
R
R
R1
R1
T
T
T1
T1
1
19
A
2
2
20
B
LOS
DET
In
In
Out
Out
Port 2
Auxiliary
DSX-1
S3
S3
S1
H
2
T
U
R
H
D
S
L
2
S
P
A
N
9
M
M
MONF
MONE
M
M
A
A
A
A
C
C
C
C
F
r
a
m
e
r
H
D
S
L
2
T
r
a
n
s
c
e
I
v
e
r
R
T
T
e
s
t
J
a
c
k
s
M
U
X
L
I
U
E
q
u
a
l
I
z
e
r
S
e
l
e
c
t
E
q
u
a
l
I
z
e
r
s
e
l
e
c
t
A
u
x
L
I
U
1
K
MONF = Monitor Facilities
MONE = Monitor Equipment
SPTF = Split Facilities
SPTE = Split Equipment