Quantum and Evolution Series Installation and Operating Handbook
6-16
input back to the output (typically used when Drop/Insert is in operation and the same PCM
bearer is cascaded through several modems).
ESC and Aux Connector
This connector is fitted as part of the IDR option and provides access to:
•
Four backward alarm form `C` outputs and four backward alarm inputs, together
with an Rx summary alarm signal for direct connection to the backward alarm
inputs. These are used in IDR mode.
•
Two audio ESC ports (4 wire 600
Ω
, +7 to -16dBm). In addition to normal IDR ESC
operation these ports may also be used in IBS modes 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. This is an emulation of the most popular modes of
the P1348/P1448 voice/data MUX card often used in SNG applications.
•
An RS232/RS422/RS485 port for synchronous/asynchronous ESC traffic. This port
replaces the shared ESC/Aux access via the Async ESC connector on the main
unit. It is used to provide access to the 8kbps synchronous IDR ESC channel. If the
Async ESC feature is available then this port provides both asynchronous access to
the 8kbps channel and a high rate asynchronous ESC in IBS/SMS and Closed
network plus ESC services.
•
An RS232/RS422 port for synchronous/asynchronous Aux traffic. This port replaces
the shared ESC/Aux access via the Async ESC connector on the main unit. The
Aux port provides 32 or 64kbps access to the IDR overhead in place of one or both
of the IDR 32kbps ADPCM audio ESC channels. In IBS/SMS, 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/SMS overhead.
Rx IF Input Option
This is a BNC female connector and can be used in either 50
Ω
or 75
Ω
-impedance mode.
The carrier signal level presented at the input of the modem should be in the range -60dBm
to -30dBm. A level of -45dBm is recommended. The maximum composite power level that
should be applied to this port is 30dB above the desired carrier, up to a maximum of 0dBm.
Rx L-band Input Option
This is a N type female connector of 50
Ω
impedance. The carrier signal level presented
at the input of the modem should be in the range -20dBm to -70dBm. A level of -45dBm is
recommended. The maximum composite power level that should be applied to this port
is +35dBc up to maximum of -10dBm
Fan
There is a fan that runs at all times while the unit is powered. This draws air in from the
sides and expels to the rear. The side vents must not be blocked.
1:1 Redundancy Connector
The Modem has a built-in 1-for-1 redundancy-controller that connects to the corresponding
port of another modem via a 9-pin male 'D' type connector. A 1:1 redundancy system
requires two modems, a 1:1 control cable between the two redundancy connectors, a data
split (`Y`) cable and passive splitters/combiners for the IF ports. An overview of 1-for-1
operation is provided in Section 8.4.
