Chapter 15. Diagnostics
Vol. IV-15-58 Alcatel-Lucent
Loopback and AIS Safety Timer Operation
For information on the operation of the Diagnostic Safety Timer associated with
the loopback and AIS controls, refer to Safety Timer Operation on page 15-50.
PRBS Generation
E1/DS1, E3/DS3, and STM1/OC3 DACs, E1 IDUs, and E1/DS1 IDUs include a
PRBS generator and G.821 receiver to support looped, and both-way tests on
tribs. The Generator provides a standard BER 2
15-1
test pattern.
•For a looped test the DAC/IDU provides the PBBS generator and G.821
receiver.
•For a both-way test, a PRBS generator on one DAC/IDU is G.821 received on
its remote DAC/IDU, and vice-versa. PRBS Generation must be enabled at both
ends of the trib.
• G.821 statistics have a standard latency of 10 seconds for availability and
errored seconds; on activation wait for 10 seconds before checking.
• With a DAC the PRBS generator transmits to and receives from the TDM bus.
Mouse-over the G.821 statistics panel to see a graphic of the connection.
PRBS Generator and G.821 Statistics Operation
Always allow at least 10 seconds for the G.821 data to stabilize when PRBS
Generation is enabled; 10 seconds after Send.
When a both-way test is to be established, the PRBS data for the DAC/IDU first
turned on accrues errors until PRBS on the second DAC/IDU is activated. The
second DAC/IDU should display no errors after its 10 second stabilization
period.
To restart a PRBS count, click Reset.
For STM1/OC3 DACs, the AIS selection inserts a PRBS15 pattern (15 bit
pseudo-random bit sequence).
The DAC ES and DAC GE plug-ins (Ethernet) do not support loopbacks or AIS.
IDU ES does not support loopbacks or AIS on its Ethernet ports; it does support
loopbacks on its trib and auxiliary interfaces and at digital and IF points.
External BER testers provide superior measurement accuracy and access to a
wider range of test and measurement functions.
To Next Page
Loading...