COBHAM Sea Tel 9711-56 IMA C Band, Installation Manual

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Configuring The Satellite Modem Interface. Sea Tel 9711-56 IMA
11-4
EAR Controlled - ECCN EAR99
the 12V pull up must be set to “ON” (See Modem I/O Voltage & 12V Pull up sections below).
Failure to do so may result in a false Rx Lock trigger when the applicable modem interface
cable is removed for any reason.
11.1.4.3. Modem I/O – Lock Input - Voltage
Use: The Modem I/O Lock Input Voltage selection defines the nominal voltage range for the
hard lined wire input for indication of Positive Satellite ID (RX Network Lock indication).
Selection Type: Mutually Exclusive Radio Buttons
Options : Voltage 3V, 5V or 12V.
Notes: Modem Type “Custom” must have been selected to allow changes to this setting.
You must refer to your satellite modems manufacturers written specifications for the
receive lock indication voltage range that it provides as an output. The receive logic level
itself is interpreted by the MXP based on the above mentioned Polarity selection (the actual
Low versus Hi polarity trigger is 50% of selected voltage range). Example: You have a
satellite modem that provides a 12VDC output range and Polarity has been set to Low.
When the detected voltage is between 0 to 6Vdc, the MXP would interpret this as a Positive
Satellite ID. Voltage between 6.1 and 12Vdc would be interpreted as a failed Positive
Satellite ID (because it is High).
If your modem provides a continuity based output (short to ground is Low, and Open is
high), you must set this selection to 12V.
11.1.4.4. Modem I/O – Lock Input - 12V Pull Up
Use: The Modem I/O Lock Input 12V Pull Up selection defines whether or not to use a built-
in 12VDC Pull up resistor for the hard lined wire input for indication of Positive Satellite ID
(RX Network Lock indication). The MXP requires a voltage input for this satellite ID
functionality.
If your modem outputs continuity based logic, the pull up circuit (ON) converts the
continuity to voltage. For all voltage based modem outputs, it MUST be set to OFF to
prevent false Positive Sat ID indications (voltage high & higher, but never low).
Selection Type: Mutually Exclusive Radio Buttons
Options : 12V Pull Up Off or On.
Notes: Modem Type “Custom” must have been selected to allow changes to this setting.
If your modem provides a continuity based output (short to ground is Low, and Open is high)
this selection must be set to “ON”. For all voltage based modem outputs, it MUST be set to
OFF.
11.1.4.5. Modem I/O – Block Output – Polarity
Use: The Modem I/O - Block Output selection defines whether or not the MXP will provide a
logic level Low or logic level Hi output when a condition exists that requires muting the IF
transmission of the system. This is known as TX Mute functionality and is a signal from the
MXP to the Satellite Modem (which in turn removes drive to the Block Up Converter
mounted on the antenna assembly). The signal flow for this feature is from the MXP to the
Satellite Modem.
Selection Type: Mutually Exclusive Radio Buttons
Options : Polarity Low or Hi.
Notes: Modem Type “Custom” must have been selected to allow changes to this setting.
You must refer to your satellite modems manufacturers written specifications for the input
required to mute the modems output to the BUC. Ascertain whether the input signal must
be Hi or Low logic to mute and whether it is continuity based logic or voltage based.
Example: If your satellite modem requires a Hi logic input (continuity or voltage) to cease
transmissions you must select Hi.
There are numerous compliance laws (FCC and other worldwide entities) that mandate the
ability and/or need to immediately mute transmit on a VSAT system when at least one of