8
Section 61245023L1-5B, Issue 2
61245023L1-5B
3. OPERATION
Once the ADTRAN T1 Nx64 HTU-R is properly
configured and installed, it should operate
transparently. This section describes how to use the
front panel LCD to access status information and
perform diagnostic loopback tests. Also, this
section describes how to use a dumb terminal
interface to configure, monitor, and test the
T1 Nx64 HTU-R.
Loopback Testing
The T1 Nx64 HTU-R provides two diagnostic
loopback tests for verifying proper data path
operation. These loopbacks are used in conjunction
with bit error rate test (BERT) equipment. The
loopbacks are valuable in troubleshooting and
isolating any system level problems that may occur
either at installation or operation of the HDSL
circuit.
Local Loopback - The T1 Nx64 HTU-R’s HDSL
transceivers are looped back at a point immediately
before the HDSL termination, or toward the DTE
interface. This loopback enables a complete
diagnostic of the HTU-R data path.
Remote Loopback - The T1 Nx64 HTU-R’s HDSL
transceivers are looped back at a point immediately
before the DTE interface, or toward the HDSL
interface. This loopback enables a complete
diagnostic of the local HTU-R data path, the HDSL
link, and the remote HTU-R data path.
Front Panel Status Information
The front panel LCD can be used to display useful
information about the HDSL interface as well as the
DTE interface. This information provides a way to
determine if an HDSL circuit is performing within
limits necessary to ensure error-free operation.
Similarly, DTE status information provides
information to determine proper operation of the
customer premises equipment.
HDSL Status
Three parameters are measured and displayed for
the HDSL interface. These parameters are available
for both Loop 1 and Loop 2. These parameters are
“SIGNAL QUALITY,” “LOOP LOSS,” and
“LOOP SYNC.”
SIGNAL QUALITY - This measurement provides a
relative indication of signal quality. A reading of
“9” indicates the best possible signal quality
whereas a reading of “0” indicates the worst
possible signal quality. Signal quality is a good
indication of BER performance on either loop.
LOOP LOSS - This measurement provides a
numeric indication of the HDSL signal attenuation.
ADTRAN specifies BER performance better than
10
-7
for a loop loss of less than 36dB. If you
encounter a loop loss of greater than 36dB, shorten
the HDSL loop length or check for excessive bridge
tap length.
LOOP SYNC - This measurement gives an
indication of the state of each HDSL loop.
INACTIVE indicates that the HDSL loop is not in
sync. SYNC indicates that the HDSL loop is
synchronized.
Test Pattern Generator
The Test Pattern generates a 511 test pattern on all
active DS0s, compares it to the pattern returned
from the far end, and records any errors in the
Pattern Results option under the Test menu. To
initiate this test pattern from the front panel LCD,
go to the Main menu and select the following menu
options as they appear:
Test menu
Bert Tests option
Test Pattern option
511 ACT.DS0s
PATTERN RESULTS - Clear results by pressing
“Enter.”
Figure 6. V.11 to RS-449 Adapter Cable Pinout
Signal Name
Frame Ground
TxD A
DTR A
RxD A
CD A
TxC A
Ext TxC A
Signal Ground
TxD B
DTR B
RxD B
CD B
TxC B
Ext TxC B
Pin
Number
1
2
3
4
5
6
7
8
9
10
11
12
13
14
Pin
Number
1
4
12
13
6
5
8
17
19
20
37
22
30
31
24
23
26
35
7
9
25
27
Signal Name
Frame Ground
TxD A
DTR A
DSR A
RxD A
TxC A
RxC A
Ext TxC A
Signal Ground
Rx Common
Tx Common
TxD B
DTR B
DSR B
RxD B
TxC B
RxC B
Ext TxC B
RTS A
CTS A
RTS B
CTS B
HTU Side
DTE Side
