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Installation
2.4 Modem Checkout
The following descriptions assume that the modem is installed in a suitable location with prime
AC power and supporting equipment available.
2.4.1 Initial Power-Up
⇒
CAUTION: Before initial power-up of the modem, it is a good idea to disconnect the
transmit output from the operating satellite ground station equipment. This is especially
true if the current modem configuration settings are unknown, where incorrect setting
could disrupt existing communications traffic. New modems from the factory are normally
shipped in a default configuration which includes setting the transmit carrier off.
Turn the unit "ON" by placing the rear panel switch (above the power entry connector) to the "ON"
position. At every power-up, the modem processor tests itself and several of its components
before beginning its main monitor/control program. These power-up diagnostics take
approximately 1 second and show no results if successful. If a failure is detected, the indications
vary by the type of fault detected. A serious failure will result in the front panel Alarm LEDs
flashing at a rate of approximately 4 times a second, and the unit beeper sounding.
Most potential failures will result in the modem giving a verbal indication of the problem on the
front panel LCD display. Status indications are shown highest priority first.
The initial field checkout of the modem can be accomplished from the front panel or in the
Terminal Mode. The Terminal Mode has the advantage of providing full screen access to all of
the modem's parameters, but requires a separate VT100 terminal or computer running a terminal
program in VT100 or ANSI mode. The modem unit is placed into terminal mode by setting two
options via the front panel. First set the <Unit: Remote – Protocol> parameter to "VT100"
(option 0), then set the <Unit: Remote – Port> parameter to "RS–232" (option 0). The <Unit:
Remote – Bit Rate> and Format also require setting to match the terminal settings. The <Unit:
Remote – Address> serves no function in the Terminal mode. See below for a quick introduction
on the use of the front panel and steps for entering parameters.
2.5 Modem Control from the Front Panel
The front panel can be used to completely control the modem setup and operating parameters.
Front panel control of the modem is more thoroughly discussed in the Operations Section, 3.1.3
"Guide to Front Panel Monitor and Control", but a quick introduction to the front panel operations
is given here to allow initial setup. The Navigation figure in Section 3.1.3 is especially useful.
The modem parameters are arranged in four matrices, one each for "Unit", "Mod", "Demod" and
"Int'f", representing Unit, Modulator, Demodulator and Interface. Each matrix is 4 to 10 columns
wide and up to 20 rows long as shown in the parameter matrix tables. The particular functional
matrix is selected by pressing one of the four buttons to the immediate right of the LCD display. In
response the modem will highlight the particular button text selected. Within each matrix the
columns designation is shown in the upper left hand corner of the LCD Display and is selected
using the left and right arrow keys. Columns common to all matrices are "Status", "Alarm" and
"Test", while others vary by the parameters required. The particular parameter within a column is
shown in the upper right hand of the LCD display and is selected using the up and down arrow
keys. The LCD display allows viewing only one of the many parameters at one time, while the
four arrow keys (↑), (↓), (→), (←), allow scrolling through the rows and columns of the parameter
matrix. The complete matrix is shown as Tables 3-1 through 3-4 in Chapter 3, "Operation" of this
manual.
In this manual operation of the keypad to access a certain parameter is shown in the format
<Function: Column – Row>. For example, to get to the Modulator IF Level the method is to
press the "Mod" key then use the left and right arrow keys to access the "IF" column and the up
Page 2-12
PSM-500/500L/500LT SCPC Satellite Modem
PSM-500/500L/500L T- Rev. 0.91
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