 HDB3 Line Signal DMTector
In both modes, the line is checked for a valid HDB3 line signals, this being shown as a green for valid HDB3 signalling or red for no HDB3 signals. Line errors (Bipolar violations or BPVs) are also indicated
o Speed 2.048Mb - G703 Interface
o G.704 Framing Analysis
o BERT (PRP15) generator/checker
o Master and Slave Timing options
o Adjustable Sensitivity: 0 to -11 or -43dB
o High Impedance Monitor Mode
o 75? or 120? matching options
o Battery powered -typically 16hours
G.703 line Bit Error Rate Test (BERT)
This provides a means of testing circuits
with an unframed data pattern. This test may be run either end-to-end, using
a pair of testers, or with a remote loop, using a single tester. With the switch
in BERT mode, the tester initially transmits continuous HDB3 zeros until valid
incoming carrier is detected .The MT2048 then generates the standard unframed
PRP-15 test pattern (215-1 pseudo-random bit sequence), and can generate on command
either single bit errors or a steady stream of errors at a rate of E-6 (2 errors
per second).It will then check the received PCM signals for the presence of the
PRP15 pattern-green LED indicates synchronisation, bit errors-yellow LED, and
a BER worse than 1 in 1000-red LED.
The user can select either Master or Slave
timing options for the BERT test allowing the tester to operate over a wide range
of network configurations. G.704 Monitoring is disabled when the MT2048 is operating
in BERT mode.
G.704 framing monitor
In this mode, the MT2048 checks the incoming PCM signals for the G.704 framing
structure. This test will normally be used to monitor live circuits carrying
traffic and will therefore normally use Hi-Z line bridging, though 75? or 120?
matching can be selected if required.
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LEDs show the presence of, and errors in, the framing signal (FAS), channel-associated
signalling (CAS), and cyclic redundancy check (CRC-4). An FAS error rate of greater
than 1 in 1000 is also indicated. Indicators are also provided to show the presence
of a distant alarm (DA) or distant multiframe alarm (DMFA). The alarm indication
signal (AIS) is similarly checked for and indicated.
Error and alarm LEDs (except DA) can be latched or momentary, according to the
switch setting. A reset button is provided to clear latched indications |
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Switches
Power: Off/On
Hi/Lo Sensiitivity: Hi = -43dB, Lo = -11dB
Impedance Matching: 75?,120?,High
Monitor Mode / Bert-master/ Bert-slave
In Master MT2048 originates the timing
In Slave MT2048 synchronises output to the clock of the received signals.
Inject Errors: ( BERT mode only)
Latch / Momentary: controls LED functions
Reset: Cancels latched error indications
LEDs
Lo Battery: ? 30 mins power remaining
Rdy/Synch:
Test pattern Synch / test pattern output
(Flashing: transmit ‘0's, Solid: transmit PRP)
Line Signal: HDB3 signal detector
(green= valid signals ,red= no HDB3 signals)
BPV: Bi-polar violations detected
AIS: All ones detected
PRP: Pattern Synch/ Errors/ Error Rate ?103
FAS: Frame Synch / Errors/ Error Rate ?103
RA: Remote Alarm detection ON/OFF
CRC4: / CRC4 errors
CAS: / CAS errors
DMFA: Distant Multiframe Alarm ON / OFF
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Line
Matching: 75? or 120?
Return Loss: >15dB (51kHz to 3.072mhz)
Dynamic Range: 0 to -11db or 0 to -43dB
Isolation: typically 3kV transmit to receive
Transmit: pulse amplitude and masks to G.703
Test Pattern: PRP15 ( 215-1 )
Physical
Size: 65x120x22mm (excluding connectors)
Weight: 140g (5oz) approx (including batteries)
Case: ABS to UL-94H
Power
Source 2 x AA cells (MnAlk recommended)
Life: typically 16 hours
Lo bat flashes when less than 30mins of battery power life remaining when using
Alkaline batteries |
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