Comtech EF Data RCF6001 - Manual (Page 25)

RCF6001 Satellite Terminal Maintenance
TM082 - Rev. 1.0 Page 4-5
3.5.1 Initial Power-Up
⇒ ⇒
CAUTION: Before initial powerup of the DMD2401 LB/ST, 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 initial and every subsequent power-up, the modem processor will test itself and several of its
components before beginning its main monitor/control program. These power-up diagnostics show no
results if successful. If a failure is detected, an Alarm LED will illuminate.
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 terminal or computer running a terminal program. The unit is placed
into terminal mode by setting two options via the front panel. First set the ‘Modem – Remote’ parameter
to ‘Terminal’ (option 3), then set the ‘Modem – Remote Port’ parameter to ‘RS–232’ (option 0). The
‘Modem – Bit Rate, Format and Parity’ also requires setting to match the terminal setting. The Modem
Remote Address serves no function in the Terminal mode. Terminal Setup is as follows:
Terminal Setup:
Baud Rate: 19.2 K
Data Bits: 8
No Parity
1 stop bit
3.6 DMD2401 Automatic Uplink Power Control (AUPC) Operation
The DMD2401 modem has an optional built-in provision for Automatic Uplink Power Control (AUPC).
AUPC attempts to maintain a constant E
b
/N
o
at the receive end of an SCPC link. This is especially useful
when operating over a satellite at Ku-Band frequencies in locations with high rainfall periods.
Note: An Asynchronous or IBS Interface is required for AUPC. Also, IBS (Async) Framing Mode
MUST be selected to provide a channel for AUPC operation.
The IBS (Async) Framer Data Mode provides a service channel between the two sites of a link permitting
the modem processors to send messages and get responses over this channel. AUPC can be set to
operate on either or both directions of a link but always requires a bi–directional channel. Therefore,
both the Modulator and Demodulator interface mode must be set to IBS (Async) for the AUPC menus to
be visible and for the AUPC function to operate properly. The AUPC functions and their descriptions are
shown below:
Function Description
AUPC
ENABLE/DISABLE Enables/Disables the AUPC to function locally
AUPC E
b
/N
o
Desired E
b
/N
0
of remote modem
AUPC MIN LVL Sets minimum output power to be used
AUPC MAX LVL Sets maximum output power to be used
AUPC DEF LVL Sets default output power to be used