Comtech EF Data CDM-550T Manual page 43

CDM-550T Satellite Modem
(CONFIG, TX) SCRAM (Scrambling)
(CONFIG, TX) CLK (Clocking)
Rev. 1.3
SELECT TX SCRAMBLING:
OFF ON (PRESS ENTER)
Select either ON or OFF, using the LEFT/RIGHT arrow keys, then press
ENTER.
When Transparent mode is selected, a V.35 scrambler is used. In Framed or
Reed-Solomon modes, a frame synchronised scrambler is used.
SELECT TX CLOCKING MODE:
INT EXT LOOP-TIMED (ENT)
Select INT (Internal), EXT (External) or LOOP-TIMED, using the LEFT/RIGHT
arrow keys, then press ENTER.
INTERNAL indicates that the CDM-550T will supply a clock to the DTE, which
is derived from its internal high-stability source.
EXTERNAL indicates that the CDM-550T expects to receive a clock from the
DTE, to which the unit can phase-lock its internal circuits.
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.
Front Panel Operation
6–13