Chapter 5 Datacom Testing
Specifying test settings
56 SmartClass E1 Tester User’s Guide
PRBS 2047 Simulates live E1 data. A pseudorandom pattern
based on an 11-bit shift register. Selects the 2
11
-1
Pseudorandom pattern, which generates a maxi-
mum of 10 sequential 0s and 11 sequential 1s.
PRBS 2 15 ITU Selects the 2
15
-1 pseudorandom pattern, which
generates a maximum of 14 sequential 0s and 15
sequential 1s. Simulates live data for 56 kbit/s to 2
Mbit/s circuits. This is the default pattern for E1.
PRBS 2 15 INV ITU Selects the inverted 2
15
-1 pseudorandom pattern,
which generates a maximum of 14 sequential 1s
and 15 sequential 0s.
PRBS 2 20 Selects the 2
20
-1 pseudorandom pattern, which
generates a maximum of 19 sequential 0s and 20
sequential 1s.
PRBS 2 20 INV Selects the inverted 2
20
-1 pseudorandom pattern,
which generates a maximum of 19 sequential 1s
and 20 sequential 0s.
PRBS 2 23 ITU Selects the 2
23
-1 pseudorandom pattern, which
generates a maximum of 22 sequential 0s and 23
sequential 1s.
PRBS 2 23 INV ITU Selects the inverted 2
23
-1 pseudorandom pattern,
which generates a maximum of 22 sequential 1s
and 23 sequential 0s.
PRBS DELAY Used for measuring round trip delay. Delay pattern
measurement requires a transmitter/receiver loop-
back, with the transmit rate equal to the receive rate.
This test measures round trip delay once per sec-
ond (or until the previous delay measurement is
complete) for the length of the test, provided pattern
sync is present. Normal BER test results (such as bit
errors and pattern sync) are not available during
delay testing
PRBS 2 20 QRSS Simulates live data. QRSS is a modified 2
20
-1 pseu-
dorandom pattern that allows a maximum of 15
sequential zeros and 20 sequential ones. 2
20
-1
pseudorandom pattern with 14-zero suppression.
LUP ALL ONES Provides a fixed test pattern of all ones (AMI
pulses). It can be used as an AIS in unframed cir-
cuits, a keep alive signal, or an idle code. This pat-
tern is required to accurately measure the E1 signal
power in dBnom.
LUP ALL ZEROS Provides a fixed test pattern of all ones. The Line
Code should be set for HDB3 when sending the All
Zeros pattern or the network will lose timing. This
pattern can be transmitted framed or unframed.
LUP QBF The Quick Brown Fox message.
LUP 1TO1 A one followed by a zero, the minimum stress on
clock recovery circuits.
LUP 1TO3 A one followed by 3 zeros.
LUP 1TO4 A one followed by 4 zeros.
Pattern Description
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