Q-Flex Satellite Modem Installation and Operating Handbook
12-5
120
Ω
RS422 compatible input, 1MHz to 10MHz in
1kHz steps via Async ESC connector
NB: When set to 10MHZ, the station reference may
replace internal reference to all internal circuitry and
reference outputs on the IF ports. The unit
automatically switches back to internal reference if the
station reference fails.
Buffer Size
Selectable in 1ms increments from 0ms to 99ms at
data rates up to 42Mbps and from 0ms to 80ms at data
rates from 42Mbps up to 55Mbps. Automatically
adjusted to slip an integer number of terrestrial multi-
frame lengths for framed rates
Buffer storage: Maximum buffer size – 256kbytes
12.5 Framing and Deframing Specifications
Parameter
Modem
Closed Network Format
Unframed, no overhead.
IBS/SMS Option Format
Intelsat IBS to IESS-309 and IESS-310 up to 10 Mbps,
and Eutelsat SMS to EESS501.
IDR Option Format
Intelsat IDR to IESS-308 and IESS-310 up to 10
Mbps.
Closed Network plus
ESC Format
Provides variable rate asynchronous ESC, optional
synchronous scrambler above 32kbps to replace error
multiplying V.35 scrambler, optional backward alarm
facility and optional timeslot ID maintenance when
used with Drop/Insert, all in minimum possible
overhead down to <0.5%