Filter
Top Products
P300H P300 Series Modem Installation and Operating Handbook Page 70
Toggle Scramblers:
1=IBS (Off) 2=RS (N/A) 3=V.35 (On) 4=Turbo (N/A)
Change, Tx/Rx, Mod/Demod, Scrambler-Custom Menu
V.35 Style Scrambler [?]
1=CCITT 2=INTELSAT V.35 (Normal) 3=FDC 4=Linkabit
Change, Tx/Rx, Mod/Demod, Scrambler-Custom V.35 Menu
NORMAL Selects the appropriate scrambler based on the current configuration, and
enables it (see table below).
FEC: No Reed-Solomon Reed-Solomon Active
Service type: Non Turbo Turbo Non Turbo Turbo
Closed Net (No ESC),
Closed Net + ESC (<32kbps),
IDR (& Custom IDR)
Custom IBS without TS32 MF
V.35 Scr Turbo Scr RS Scr RS Scr
IBS/SMS,
Closed Net + ESC (>=32kbps), IBS/SMS synchronous scrambler
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.
Other This allows non standard scrambler operation to match the configuration of other
non standard equipment which leads onto the following menus:
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.
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 152 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.