P300H
P300 Series Modem Installation and Operating Handbook
Page 128
6.16.5 Test, Int' BERT, OFF/CHANNEL Menu
Channel for BER Test: [ESC]
1:Main data 2=ESC 3=Aux
Test, Internal BERT, Channel Menu
The test may run through the Main, ESC or Aux channels.
Óß×Ò
This first generates an `are you sure` screen before substituting the PRBS in
place of the Tx main traffic channel and monitoring for errors on the Rx Main
traffic channel. Note that for Closed Network mode only (ie no overhead at all)
the BER Tester cannot currently inject a test pattern into the main traffic
channel
(a warning is issued on the screen). It can however receive and monitor a test
pattern injected by equipment at the distant end of the link. On a link where it is
necessary to use the BER Tester, switch to Closed Net
Plus ESC
mode, and if
not using the ESC set it for the lowest possible Baud rate which will result in an
overhead of <0.5%.
ÛÍÝ ñ ßËÈ
ÛÍÝ
&
ß«¨
are defined below for the different service types. If either ESC or
Aux are selected but the channel has not been defined, then the user is
prompted to define the channel (and must then re-select the channel from this
screen).
Closed Network
ESC
&
Aux
channels are not available in Closed Network mode (as there
is no overhead in which to carry them).
Closed Net Plus ESC
Closed Net Plus ESC mode is only available if the Async ESC feature is
available (standard on P300-IBS and above). The
ESC
channel Baud rate
is used to determine the overhead added to the main data, allowing the
minimum possible overhead to be added (ie the minimum bandwidth to be
used), to provide the Async ESC Baud rate required. When the ESC
channel is used for BER testing the Async ESC is disabled and whatever
bandwidth was assigned to the Async ESC channel is used synchronously
for BER testing. The data rate to the satellite (main data + overhead)
remains unchanged.
There is no
Aux
channel facility in Closed Net Plus ESC, as this mode is
specifically designed to minimise the satellite bandwidth used, and hence
all overhead is assigned to the ESC channel.
IBS/SMS
IBS/SMS mode is only available if the IBS/SMS feature is available
(standard on P300-IBS and above). The
ESC
channel is the channel,
which is normally used to carry asynchronous data from earth station to
earth station (typically used for distant end M&C). When selected as the
BER test channel Async ESC data is not passed and the channel is used
synchronously for BER testing. It is only possible to define an ESC channel
in IBS/SMS mode for the BER test to run through if the Async ESC feature
is available (standard on P300-IBS and above). The ESC channel may be
configured to provide rates up to 4.6% of the main data rate for BER
testing.
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