89
2.048Mb
p
s Wireless Modem
TECHNICAL: 0118 931 2233
• For E1 and Fractional E1, verify that the balanced/unbalanced configuration of the LIU (set
by the jumpers on the LIU board) matches that of the end equipment.
Problem 6: The radio link is fine, but the voice quality/data rate is poor, or the end equipment loses synchronization from time to time.
Probable cause:
• There is an echo on the voice channels created by the end equipment.
• Low data rate on a high bandwidth link, which results from the transmission delay of the
link or from errors on the link.
• End equipment loses synchronization (even on a link featuring low radio bit error rate) due
to long bursts of errors.
To reduce echo on voice channels:
1. From the MCP Parameters menu, select Total Link Delay.
2. Select a reduced delay setting.
Note: The better the radio link quality the lower the delay that can be set without introducing
errors. Where the delay cannot be reduced, an external echo canceller is required. In
fractional E1/T1 applications, use the built-in echo canceller to reduce echo in voice
channels
To improve data rate:
1. From the MCP Parameters menu, select Total Link Delay. The Total Link Delay parameter
controls the trade off between error rate and delay.
2. Select the required delay setting and test how the new setting affects your performance.
Note: Low delay implies less correction on the raw radio error rate.
To view isolated bursts of errors:
• From the Counters and Tracers menu, select Display Timer Tracer errors versus time and
Display Time Tracer max consecutive errors versus time to view isolated bursts of errors or
noisy reception periods.
• From the Counters and Tracers menu, select Set Time Tracer resolution to view the Time
Tracer time resolution. Change the resolution to “zoom-in” or “zoom-out” in order to locate
and understand the error bursts.