LTPH-UM-1109-01, Issue 1 | Testing |
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A1LB, A2LB, and A5LB Test Procedures
Using the codes listed in Table 17, a network tester can activate NLOC or NREM loopbacks (or SMJK, if enabled). A tester at the customer premises can activate CLOC, CRG, or CREM loopbacks. All loopbacks shown in Table 17 can also be initiated from the H2TU-C-231 front-panel MODE and SEL pushbuttons (see “Setting Options through MODE and SEL” on page 9).
Table 17. Addressable Repeater Loopback Commands (A1LB, A2LB, A5LB)
Name | Binary Code (a) (Hexadecimal Equivalent) | Description |
ARMING or NI LPBK (inband) | 11000-11000 ... | Arming code |
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ARMING or NI LPBK (ESF Data | 1111-1111-0100-1000 (FF48) | Arming code |
Link) | | |
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LPDN or DISARM (inband) | 11100-11100 ... | Disarming code |
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IR LPDN or DISARM (ESF Data | 1111-1111-0010-0100 (FF24) | Disarming code |
Link) | | |
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IOR LPBK (NLOC or CREM) | 1101-0011-1101-0011 (D3D3) | NLOC—DSX-1 signal is looped back to the network |
230-232 bit errors | | at the H2TU-C-231. |
229-231 bit errors (b) | | CREM—DS1 signal from customer is looped back to |
| | the customer at the H2TU-C-231. |
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ILR-2 LPBK (NREM or CLOC) | 1100-0111-0100-0010 (C742) | NREM—DSX-1 signal is looped back to the network |
20 bit errors (c) | | at the H2TU-R. |
| | CLOC—DS1 signal from customer is looped back to |
| | the customer at the H2TU-R. |
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IR LPDN | 1001-0011-1001-0011 (9393) | Loopdown (H2TU-C or H2TU-R) |
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IR QUERY LPBK | 1101-0101-1101-0101 (D5D5) | Query loopback |
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IR ALTERNATE QUERY LPBK | 1101-0101-1110-1010 (D5EA) | Alternate query loopback |
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TIME-OUT OVERRIDE | 1101-0101-1101-0110 (D5D6) | Loopback time-out override |
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Far End NI ACTIVATE (d) | 1100-0101-0101-0100 (C554) | Unblock AIS |
IOR POWER DOWN (H2TU-C) (e) | 0110-0111-0110-0111 (6767) | Removes HDSL2 line power |
(a)The leftmost bit arrives first in all sequences. The detection algorithm functions reliably with a random 10-3BER 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, including 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, including 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)Sending the Far End NI Activate code is not required in A5LB because it is always activated.
(e)The IOR Power Down code must remain present for the duration of the powerdown mode. When this code is removed, the HiGain HDSL2 system returns to its normal unlooped and unarmed state.
H2TU-C-231 List 2 | January 9, 2002 | 49 |