A2Lb Test Procedures - ADC HiGain H2TU-C-231 Manual

Testing

A2LB Test Procedures

Using the codes listed in
enabled). A tester at the customer premises can activate CLOC or CREM loopbacks. All loopbacks shown in
Table 23 can also be initiated from the H2TU-C front-panel MODE and SEL pushbuttons (see
through MODE and SEL" on page
Loopback
ARMING or NI LPBK (in-band)
ARMING or NI LPBK (ESF Data Link)
IR LPDN or DISARM (in-band)
IR LPDN or DISARM (ESF Data Link)
IOR LPBK (NLOC or CREM)
230-232 bit errors
(b)
229-231 bit errors
ILR-2 LPBK (NREM or CLOC)
(c)
20 bit errors
IR LPDN (except SMJK)
IR QUERY LPBK
IR ALTERNATE QUERY LPBK
TIME-OUT OVERRIDE
FAR END NI ACTIVATE
IOR POWER DOWN (H2TU-C)
(a) The leftmost bit arrives first in all sequences. The detection algorithm functions reliably with a random 10
on the facility. The entire arming and loopback sequence can also be initiated at the remote H2TU-R location.
(b) The H2TU-R identifies CREM (and the H2TU-C identifies NLOC) with 231 bit errors, excluding the frame bits. When framed
data is being sent in the AUTO framing mode, the number of the 231 bit errors detected by the test set varies from 229 to 231,
depending on whether or not the test set counts frame errors as bit errors, and on the number of frame bits contained in the
block of 231 error bits. The H2TU-R and H2TU-C generate this bit pattern in a series of discontinuous bursts containing 20-bit
errors each, excluding frame bits. Those test sets that do not count frame error bits as data bit errors will indicate fewer bits than
the H2TU-R and H2TU-C transmit for a CI and NI loopback.
(c) The H2TU-R is assigned the ILR-2 loopback code. It responds with 20 bit errors (excluding the frame bits).
(d) The IOR Power Down code must remain present for the duration of the powerdown mode. When this code is removed, the
HiGain system returns to its normal unlooped and unarmed state.
To perform the A2LB test procedures:
1 Send the in-band Arming and NI LPBK code 11000 to the H2TU-C for at least 5 seconds.
2 Monitor the output of the H2TU-C for the return of the pattern. Return of the pattern indicates one of the
following:
•
The H2TU-R has looped up (if the SMJK Loopback option is enabled)
•
An external NID has looped up (if the SMJK Loopback option is disabled), and the H2TU-C and
H2TU-R have been armed.
3 Verify, if possible, that the H2TU-R Loopback LED is either flashing yellow at four times per second
(indicating that the system is armed), or is a steady yellow (indicating that it is both armed and in SMJK
loopback). The H2TU-C Status LED also flashes yellow when the system is armed.
52
Table 23, a network tester can activate NLOC or NREM loopbacks (or SMJK, if
9).
Table 23. Addressable Repeater Loopback Commands (A2LB)
(a) (Hexadecimal
Binary Code
Equivalent)
11000-11000 ...
1111-1111-0100-1000 (FF48)
11100-11100 ...
1111-1111-0010-0100 (FF24)
1101-0011-1101-0011 (D3D3)
1100-0111-0100-0010 (C742)
1001-0011-1001-0011 (9393)
1101-0101-1101-0101 (D5D5)
1101-0101-1110-1010 (D5EA)
1101-0101-1101-0110 (D5D6)
1100-0101-0101-0100 (C554)
(d)
0110-0111-0110-0111 (6767)
September 28, 2001
LTPH-TP-1034-01, Issue 1
Description
Arming code
Arming code
Disarming code
Disarming code
NLOC—DSX-1 signal is looped back to the network at
the H2TU-C.
CREM—DS1 signal from customer is looped back to
the customer at the H2TU-C.
NREM—DSX-1 signal is looped back to the network at
the H2TU-R.
CLOC—DS1 signal from customer is looped back to
the customer at the H2TU-R.
Loopdown (H2TU-C or H2TU-R)
Query loopback
Alternate query loopback
Loopback time-out override
Unblock AIS
Removes HDSL2 line power
-3
"Setting Options
Bit Error Rate (BER)
H2TU-C-231 List 4E