Product Manual - DM991 Series V Family - 204.4092.08
62
12.
TESTS
The tests in the DSL interface can be executed via management, through the keys in the frontal panel
(LAL, LDL and LDR, only for DM991S/SE models), or through the CT140 (LDR) and CT141 (LAL) signals,
coming from the digital interface. Remember that signals CT140 and CT141 should be set up as
controlled in the digital interface, so that testing can be enabled.
LDR reception can be enabled by the management as well as by DIP A8 (only for DM991S/SE models).
The tests in the E1 and digital interface can only be run by the management.
To initiate a test in an interface, first it is necessary to disable any test that interface may be running
(which means it is only possible to run one test at a time in each interface). The only exception is the LDR
test combined with the BERT test. In that case, you have to enable RDL first and then the BERT test.
12.1. G.shdsl Interface Tests
12.1.1. Local Digital Loopback Test- LDL
This test helps the external and internal data link status verification. Two loopbacks are done. The internal
loopback makes the data coming from the tributaries to return to them. The external loopback makes the
external data coming from the G.shdsl to be retransmitted by this interface. Figure 23 shows the test
conditions.
Figure 23. DM991 - Local Digital Loopback on G.shdsl Interface
12.1.2. Local Analogue Loopback Test - LAL
The local analogue loopback tests serves to test the analogue part of the interface circuits. The data
transmitted by the DSL interface also return to the tributaries and the data externally received by the
aggregate is discarded. Figure 24 shows the test conditions.
Figure 24. DM991 - Local Analogue Loopback Test on G.shdsl Interface
12.1.3. BERT Test
The used BERT test standard is the 511 (2
9
- 1). The BERT is generated from the G.shdsl interface and it
is sent outside the equipment (line), therefore being able to be used to test its own data link, to which is
connected. The BERT is generated in the number of data channels in which the interface connects and
rewrites the user’s data.
When the equipment is in BERT it will send mark (all bits equal 1) to the tributaries. Figure 25 shows the
pattern generation in this interface.
Summary of Contents for DM991C
Page 1: ...DM991 SERIES V DM991C DM991CE DM991S DM991SE PRODUCT MANUAL 204 4092 08 rev 08 Date 8 12 2008 ...
Page 66: ...Product Manual DM991 Series V Family 204 4092 08 66 Figure 31 LDL Test Converter Mode ...
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