Test Pattern Monitoring
Access-T provides a framed QRSS test pattern for testing looped or end-to-end
circuits. QRSS (Quasi-Random Signal Source) is a repeating pattern of 2
20
-1
(1,048,575) bits which simulates “live” data.
The QRSS test pattern can be transmitted over the entire T1 bandwidth, mapped
into the DS0s assigned to a specified DTE port or aux port, or mapped into all
idle DS0s.
Whenever it is transmitting QRSS, Access-T will monitor the received DS0s for
the QRSS pattern, indicating whether pattern synchronization has been achieved
and displaying the number of bit errors detected during pattern sync. If no
loopback is in effect, testing in both directions can be accomplished by transmitting
QRSS in the same DS0s from the Access-T at each end of the T1 link.
When used with a CS Line Loopback at the far-end Access-T, channelized QRSS
transmission allows testing of a circuit without interrupting data flow in the DS0s
which are not looped back or carrying QRSS. For example, the DTE Port 1
channel could be looped back and tested without affecting data in the other DTE
Port channels.
Note:
Within a DS0, the QRSS test signal always uses the full
64 kbps (8 bits per channel per frame).
ACST-0351-005
Chapter 2
June 1996
Access-T Functional Overview
2-25