
P300H
P300 Modem Installation and Operating Handbook
Page 138
8.7.2
Closed Network Plus ESC via the Custom Service menu
Early versions of the embedded code for the P400 Series of satellite modems did not
directly
provide a
Closed Net Plus ESC option, although the feature is still available (under a different name) from the Custom
Service menu dialogue.
If you wish to use Closed Net Plus ESC on a P400 series modem it is probably easier to load the modem
with the latest embedded code (downloadable from our Web site) and use the Closed Net Plus ESC facility
directly. This latest P400 software will also provide the facility on P420's and P440's which are fitted with
an ASIC IFU ("IFU:2", see Appendix C1), which previously could not provide the facility as they had no
"Custom" option on the service menu. The Custom Menu however has always been available on P460's
and P480's.
If you do wish to use the Custom menus to define Closed Net Plus ESC operation, the table below specifies
the parameters to enter at each menu which follows the
Custom
option from the Tx/Rx Service selection
screen.
Main Data Rate
Based On
TS32 MF
Backward Alarm
No. of Back' Alm
Overhead Mode
>= 32kbps
IBS
Normal
User choice
One
Min O/H
< 32kbps
IBS
No TS 32 MF
User choice
N/A (no TS32 MF)
Min O/H
In both cases under the
ESC
,
DEFINE
dialogue set the proportion of the overhead assigned to the async
ESC as
Maximum (all remaining)
and set the Aux channel to
Off
, so that as much as possible of the
overhead is used for the ESC reducing the total overhead added to the data. The final satellite data rate
including overhead can be displayed on the
INFO
,
VIEW CONFIG
,
TX/RX
screens.
Note: As the overhead used relates directly to the data rate, ESC & backward alarm settings, then for two
modems to interwork the following parameters must match on both modems:
L
Main data rate.
L
Async ESC Baud Rate and Character length / Parity.
L
Backward Alarm option (ie both enabled or both disabled).
L
Baseband modes (ie both Continuous Data or both Drop/Insert).
A Closed Net Plus ESC facility as described above (using the Custom Service options) is
identical
with
the Closed Net Plus ESC facility which may be directly activated in software V1.50 or greater from the
Service, Closed Net, ESC menu.