Paradise Datacom P300-VSAT Installation & Operating Handbook page 68

NORMAL
Other
Change, Tx/Rx, Mod/Demod, Scrambler-Custom Menu
Pressing 1, 2, 3, or 4 toggles each available scrambler between On and Off. Scramblers which are not
available are shown as N/A (Not Available) as they are out of circuit (eg Reed-Solomon scrambler when
RS is Off). This screen specifically allows you to enable more than one scrambler, in order that you might
match the (mis)configuration of other equipment which allows the operator to accidentally switch multiple
scramblers on. When the V.35 style scrambler is enabled a subsequent menu is displayed.
Change, Tx/Rx, Mod/Demod, Scrambler-Custom V.35 Menu
This screen then allows selection between CCITT V.35, INTELSAT V.35, FDC (Fairchild), and Linkabit
types. These are all different interpretations of the poorly defined V.35 scrambler specified by the CCITT.
Unless you are trying to inter-operate with another manufacturers equipment known to have an incorrect
scrambler, select INTELSAT mode as this is the most common.
Refer also to section 8.9 on page 141 which describes in more detail the different scramblers, and
interworking between manufacturers.
The operator is warned of unusual scrambler settings when SETUP-CHECK is requested.
P300H
Selects the appropriate scrambler based on the current configuration, and
enables it (see table below).
Service type:
Closed Net (No ESC),
Closed Net + ESC (<32kbps),
IDR (& Custom IDR)
Custom IBS without TS32 MF
IBS/SMS,
Closed Net + ESC (>=32kbps),
Custom IBS with TS32 MF
The rationale behind this "NORMAL" option is deceptively simple: Following
Intelsats example of using Reed-Solomon with IBS or IDR, we have simply used
the first synchronous scrambler in the transmit chain even when two or more are
available. Also any synchronous scrambler is used in preference to the V.35 self
synchronising scrambler, as this will multiply received errors degrading
performance.
This allows non standard scrambler operation to match the configuration of other
non standard equipment which leads onto the following menus:
Toggle Scramblers:
1=IBS (Off) 2=RS (N/A) 3=V.35 (On) 4=Turbo (N/A)
V.35 Style Scrambler [?]
1=CCITT 2=INTELSAT V.35 (Normal) 3=FDC 4=Linkabit
P300 Modem Installation and Operating Handbook
FEC: No Reed-Solomon
Non Turbo Turbo
V.35 Scr Turbo Scr
IBS/SMS synchronous scrambler
Reed-Solomon Active
Non Turbo Turbo
RS Scr RS Scr
Page 68