Chapter 4
Test Results
G.821 results
Data Communications and Diphase Testing Manual
Page 36
21148872, Rev. 002
January 2016
G.821 results
G.821 results provide statistics in accordance with the ITU-T G.821 specification for
error performance. These results are derived by observing the received bit error counts
and received bit counts at one second intervals, and classifying these seconds as avail-
able, unavailable, severely errored, or error free.
provides descriptions of the test results in the G.821 category.
Rx Async Data Losses
Number of receiver synchronization losses resulting
from a loss of data after at least one data transition has
occurred.
Characters Sent
Count of the number of transmitted characters since the
last test restart in asynchronous timing mode.
Table 13
Data results (Continued)
Test Result
Description
Table 14
G.821 results
Test Result
Description
%AS
Number of available seconds divided by the number of test
seconds since initial pattern synchronization, expressed as a
percentage.
%EFS
Number of error-free seconds divided by number of seconds
since pattern synchronization, expressed as a percentage.
%ES
Number of seconds during which one or more bit errors were
detected divided by number of seconds since the last test
restart, expressed as a percentage. The unit stops calculating
this result when the UAS result starts to increment (see
).
%SES
Number of severely errored seconds divided by the number of
available seconds, expressed as a percentage. The unit stops
calculating this result when the UAS result starts to increment
(see
AS
Number of available seconds since initial pattern synchroniza-
tion until 10 consecutive seconds with a BER exceeding 10
-3
occurs.
EFS
Number of seconds during which no bit errors were detected.
ES
Number of seconds since unit detected a signal and acquired
pattern synchronization during which one or more bit errors
were detected. Count stops when UAS result starts to incre-
ment (see
).
SES
Number of available seconds during which BER is greater
than 10
-3
. Count stops when UAS result starts to increment
(see
