Figure 1-3. Modular Construction - Comtech EF Data SDM-650B Installation And Operation Manual

Introduction
Test points are located on the front board edge of the modulator, demodulator, and decoder
PCBs. Refer to Section 6.1.4 for listings and diagrams of the test points.
All controls and indicators for operation of the modem are located on the front panel. For
more information, refer to Chapter 4.
The chassis also contains the power supply; a fan is located on the rear panel.
The modem consists of the following assemblies:
Chassis with Power Supply
PCB, M&C
PCB, Modulator
PCB, Demodulator
PCB, Sequential Decoder
PCB, Front Panel Control Board
PCB, Mother Board
PCB, Digital Interface V.35
PCB, Digital Interface DS1
PCB, Digital Interface MIL-STD-188-114
PCB, Doppler Buffer
PCB, Asynchronous Overhead Channel Unit
Note: X = various options available on the modulator, demodulator, and decoder
boards.
1–4

Figure 1-3. Modular Construction

Assembly
SDM-650B Satellite Modem
Drawing #
AS/1099
AS/0356
AS/0773-X
AS/0778-X
AS/0365-X
AS/0361
AS/0979-1
AS/0627-2 (Optional)
AS/0569 (Optional)
AS/0627-3 (Optional)
AS/3812 (Optional)
AS/1311-X (Optional)
Rev. 5