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5012-91 Installation Manual
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 numerous
predefined conditions are met. In most cases, these are conditions that ultimately determine that
the system is not accurately pointed to the desired satellite. However there are some conditions
where this may not be true, as is the case of the antenna being pointed at a pre-defined "Radiation
Hazard Zone", which discussed in detail within another chapter of this manual, is programmed in as a
Blockage Zone, thus the name Block Output.
Configuring The Satellite Modem Interface.
11-4
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