Mocomtech CDM-570 - Manual (Page 142)

CDM-570/570L Satellite Modem with Optional IP Module Revision 4
Front Panel Operation MN/CDM570L.IOM
6–18
6.7.8 (CONFIG, TX) SCRAMBLING
The options are:
Default-On - the appropriate scrambler type is automatically selected
IESS-315-On - this only applies when Turbo is installed and has been selected as the
FEC type
Off - No scrambling
As before, the options are displayed all of the time, but the ◄ ► arrow keys will force
the cursor to skip past an unavailable choice.
The default scrambler types are:
Uncoded ITU
V.35 (Intelsat variant)
Viterbi, no framing: ITU V.35 (Intelsat variant)
Viterbi, EDMAC frame: Comtech proprietary, frame synchronized
Viterbi + RS or TCM/RS: Per IESS-308, frame synchronized
TPC or LDPC: Comtech proprietary, frame synchronized
8-QAM TPC: ITU V.35 (Intelsat variant)
6.7.9 (CONFIG, TX) CLOCKING
Select Int (Internal), Ext (External) or Loop-Timed, using the ◄ ► arrow keys, then
press ENTER.
Internal indicates that the CDM-570/570L will supply a clock to the DTE, which is
derived from its internal frequency reference. If the IP Module is installed and the
selected Data Interface is IP, then Internal is the only valid selection.
External indicates that the CDM-570/570L expects to receive a clock from the DTE, to
which the unit can phase-lock its internal circuits. (If G.703 is selected as the Interface
type, the software will force the clock mode to External.)
Loop-Timed indicates that the transmit timing source should be the receive clock, from
the direction of the satellite. This is a useful mode, in that no external connection needs to
be made in this mode. If the demodulator loses lock, or if there is no receive signal
present, the internal clock is substituted. Note also that this mode will work even with
asymmetric Rx and Tx data rates.
Tx Scrambling:Default-On
IESS-315-On Off (
◄ ►,ENT)
Tx Clocking Mode: Int
Ext Loop-Timed (
◄ ►,ENT)
IMPORTANT