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Q-Flex Satellite Modem Installation and Operating Handbook
5-12
•
On-line LED
This LED mirrors the front-panel Tx Carrier LED allowing the operator, from the rear
of the modem, to ascertain the carrier status and to identify which modem in a 1:1
redundant pair is offline.
•
Optional Terrestrial Interface Positions
There are four terrestrial interface positions that can be fitted with a variety of
interface cards including EIA-530, G.703, Quad E1, Quad ASI, LVDS, HSSI and
STM-1/OC-3/Optical Ethernet.
The G.703 interface card supports T1, E1, T2, E2, T3 and E3 data rates. Balanced
operation is provided on two RJ45 connectors while unbalanced operation is via two
BNC connectors. For balanced operation, T1 line impedance is 100
Ω
, E1 line
impedance is 120
Ω
and T2 line impedance is 110
Ω
. Unbalanced E1, T2, E3 and T3
line impedance is 75
Ω
. Line impedance is software selectable.
•
ESC and Aux Connector (IDR Option Card)
When fitted, the IDR option card provides access to:
•
Four backward-alarm ‘form-C’ relay outputs and four backward-alarm inputs,
together with an Rx summary-alarm signal.
•
Two audio ESC ports (with 4-wire 600
Ω
impedance and input range +7dBm to -
16dBm) for use in IDR operation. These ports may also be used in IBS services
to generate a 64kbps IBS carrier comprised of two 32kbps ADPCM audio
channels or a 128kbps IBS carrier comprised of 64kbps data (from the main
data interface of the modem) plus two 32kbps ADPCM audio channels.
•
An RS232/RS422/RS485 port for synchronous and asynchronous ESC traffic.
This port replaces the shared ESC/Aux function on the rear-panel Async ESC
connector. It provides an 8kbps synchronous IDR ESC channel. If the Async
ESC feature is available then this port provides an asynchronous 8kbps channel
and a high-rate asynchronous ESC in IBS and Closed N ESC services.
•
An RS232/RS422 port for synchronous and asynchronous Aux traffic. This port
replaces the shared ESC/Aux function on the rear-panel Async ESC connector.
The port provides a 32kbps or 64kbps IDR overhead channel in place of one or
both of the IDR 32kbps ADPCM audio ESC channels. In IBS, this port may be
configured to provide either the IBS ‘low-rate Intelsat oversampled ESC facility’
or a higher-rate synchronous channel within the IBS overhead.
•
Rx IF Input
This is a 50
Ω
/75
Ω
BNC female connector. The carrier signal level at the input of the
modem must be in the following range:
Minimum signal level: -115 +10 log (symbol rate) dBm
Maximum signal level: -80 + 10 log (symbol rate) dBm