Appendix C
Test Patterns and Loop Codes
Test patterns
CT-650 Command-Line Reference Guide
Release 9.4
193
X
2^20-1
1,048,575-bit pseudorandom pattern which generates a maxi-
mum of 19 sequential zeros and 20 sequential ones. This pattern
conforms to CCITT Recommendation O.151.
X
X
X
2^20-1-
QRSS
1,048,575-bit quasirandom signal source pattern generates a
maximum of 14 sequential zeros and 20 sequential ones. Pattern
simulates live data for T1 applications. Pattern meets excess
zeros and ones density requirements
X
2^23-1
8,388,607-bit pseudorandom pattern which generates a maxi-
mum of 22 sequential zeros and 23 sequential ones. This pattern
conforms to CCITT Recommendation O.151.
X
X
X
2047-QRSS
DS1/FT1 Rate — 2047-bit quasirandom signal source pattern
generates a maximum of 10 sequential zeros and 11 sequential
ones. Pattern meets excess zeros and ones density require-
ments.
DDS Rate — 2047-bit quasirandom signal source pattern gener-
ates a maximum of 10 sequential zeros and 11 sequential ones.
Used to test DDS and other circuits operating between 9.6 and
56 kb/s. Pattern meets excess zeros and ones density require-
ments.
X
X
X
3IN24
Fixed F0100 0100 0000 0000 0000 0100… test pattern. Pattern
provides minimum ones density (12.5%) and maximum excess
zeros (15) requirements to stress circuits. When framed, the pat-
tern violates minimum ones density requirements. Pattern
aligned with F-bits as indicated.
X
X
X
511-QRSS
DS1/FT1 Rate — 511-bit quasirandom signal source pattern
generates a maximum of 8 sequential zeros and 9 sequential
ones. Pattern meets excess zeros and ones density require-
ments.
DDS Rate — Used to test DDS and other circuits operating
below 9.6 kb/s.
X
Bridgetap
Bridge tap detection test pattern. Pattern determines if bridge
taps are connected to a T1 span by sequentially testing the span
with 21 test patterns that have a variety of ones and zeros densi-
ties. Sequence takes approximately 10.5 minutes to transmit.
Use AMI coding to transmit patterns properly; B8ZS encoding
makes testing less effective. Refer to
for
specific test pattern sequences.
Table 12
Digital test patterns (Continued)
DS3
DS1
FT1
DD
S
Pattern
Description
Summary of Contents for CT-650
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