Pattern | Description | Application |
QRSS | 1,048,575 bit pattern | Simulates live traffic including both high and low-density sequences |
1 IN 8 | Eight bit pattern of a 1 and 7 zeros | Checks clock recovery on circuits optioned for B3ZS |
2 IN 8 | Eight bit pattern of two ones and 6 zeros | Used to determine correct optioning of AMI or B3ZS line coding |
3 IN 24 | 24 bit pattern with 3 ones and 15 consecutive zeros. 12.5% ones density | Stresses AMI optioned circuits for minimum ones density and maximum consecutive zeros performance. Forces zero substitutions in B3ZS optioned circuits |
ALL ONES | All ones sent as payload in a framed sequence | Stresses ability of circuit to operate under maximum power conditions |
ALL ZEROS | All zeros sent as payload in a framed sequence | Checks for B3ZS optioning. Circuit will drop if optioned for AMI |
1010 | Alternating 1s and 0s | Stresses ability of circuit to operate under 50% power conditions |
PRBS-9 (511) | 511 bit pseudo-random pattern | Test sub-rate DDS circuits operating below 56 kb/s |
PRBS-11 (2047) | 2047 bit pseudo-random pattern | Test 56 kb/s DDS circuits |
PRBS-15 | 32,767 bit pseudo-random pattern. Generates up to 14 consecutive zeros and 15 consecutive ones | Tests to CCITT Recommendations O.151 and G.703. Provides maximum number of zeros for testing non‑B8ZS circuits |
PRBS-20 | 1,048,575 bit pseudo-random pattern Generates up to 19 consecutive zeros and 20 consecutive ones | Used to test synchronous T1 circuits only |
PRBS-23 | 8,388,607 bit pseudo-random pattern Generates up to 22 consecutive zeros and 23 consecutive ones | Used to test synchronous T1 and T3 circuits |