The
DSL Measurements
mode and screen provides all the measurements related to the DSL layer and is displayed
automatically after achieving showtime. The BX100A/V synchronization process can be outlined as follows;
1.
Activation, Discovery or Handshaking
- Powering on the unit takes the DSL modem into activation and
acknowledgment phase, also known as handshaking. The goals of this phase are to determine which tones can be used and
how many bits can be assigned to each tone. Initialization typically uses two pilot tones to begin activation. Normally the
modem initiates the process when it is turned on and connected to the DSL line. Messages are sent using the pilot tones to
ensure that both ends are ready for transceiver training process.
2.
Training
- DSLAM measures and adjusts the power output to equalize the circuit. Unless configured otherwise, it
negotiates the fastest possible speed based on local loop conditions.
3.
Channel Analysis
- DSLAM tells the modem which options are configured and sends a predefined medley of tones so the
modem can report its signal-to-noise ratio.
4.
Exchange
- DSLAM sends the minimum signal-to-noise ratio and decides on the power output per tone.
5.
Show Time
- Initialization concludes in which the line is active and higher layer protocols such as ATM can begin
negotiation to transfer data over the connection.
The following measurements and parameters are displayed in the various Tabs;
Link Up
Tab: provides a snap shot of the link at initial turn up.
Current
Tab: provides the current status of the link parameters and conditions.
SNR
Tab (BX100A fitted with TI chipset): provides a tabular and graphical display of the Signal to Noise Ratio per tone.
Bits
Tab: provides a tabular and graphical display of the bit allocation per tone.
Alarm
Tab: provides information on any alarm occurring or having occurred on the line.
Events
Tab: provides a log of all events that have occurred on the link since the test was started or measurement was
cleared or reset.
The Measurement Action Pull down menu performs the following functions;
Close:
Closes the Pull Down Menu
Link Down/Link Up -
a "Dying Gasp" signal, it sent to the DSLAM. The dying gasp message shows that the connection
went down because of loss of power and not because the cable was accidentally cut between the modem and DSLAM.
Retrain:
Clear Measurement:
Resets the measurement counter.
BX100A Link-Up results
BX100V Measurement Action Menu
Link Up
Tab: The initial showtime results are displayed. The screens may vary from BX100A to BX100V models, and from test
mode to test mode, however the result information maintains and retains the same basic definition/s.
BX100A/V e-Manual D07-00-001 Rev E01
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