1. CECOM LAR Tropo Operation Course
MD-1026 (GM)
CECOM LAR Course
CONUS Branch
FT McPherson, GA
TITLE PAGE
MD-1026 GM

2. CECOM LAR Tropo Operation Course
Purpose
Converts CDI to NRZ
Routes cable DVOW to/from OCU
Routes cable AVOW to/from AVOW unit
RECAP SLIDE
MD-1026 GM

3. CECOM LAR Tropo Operation Course
Specifications
Dimensions 19” X 8.5” X 12” deep
Weight 35 lb.
Input Power 115 VAC  10%, 47 to 420 Hz
Data Rates- 72 KB/s to 4608 KB/s
RECAP SLIDE
MD-1026 GM

4. CECOM LAR Tropo Operation Course
Block Diagram
1. Show NRZ and CDI sides of equipment.
2. Show where DVOW is extracted.
MD-1026 GM

5. CECOM LAR Tropo Operation Course
C&I
A- TEST- This push-button switch energizes the BITE circuit in a test mode to light all fault lamps on the GM or fault LED on A4 - A16.
B- LOSS OF INPUT- This lamp lights if the GM loses an external input. The associated CCA fault lamps also lights. Operator should check the LS (Line Side) light on the Alarm Monitor. If On, the LOI is from the Cable Side
C- PWR SUPPLY- A lamp, which lights if one or more power supply voltages is out of tolerance. Operator should open cover of Power Supply to see which CCA Fault Lamp is lit.
D- SUMMARY- Illuminates when the GM detects a fault.
E- Label- A label on the front panel which indicates internal controls and indicators.
F- Power ON/OFF- Switches 115 V AC on/off
G- POWER- A lamp indicates 115 V AC has been applied.
H- MAIN POWER- A front panel Circuit Breaker that provides over current protection
MD-1026 GM

6. CECOM LAR Tropo Operation Course
C&I
A- FAULT-This red LED indicates a fault has been detected on the AC input CCA.
B- FAULT- The red LED indicates a fault has been detected on the multi VDC CCA.
C- FAULT- A red LED indicating a fault has been detected on the 5 VDC CCA.
D- FAULT- A red LED lights if DPHS A CCA malfunctions or lacks proper input.
E- FAULT- A red LED lights if DPHS B CCA malfunctions or lacks proper input. This usually means that there is no Orderwire, and Switch G is set to SYS. Try setting Switch G to MAINT
F- FAULT- A red LED lights if BITE 1 CCA malfunctions.
G- OW SYST/ MAINT- Toggle switch selects either System Orderwire or MAINT analog voice orderwire function. This will normally be in the SYS position as Orderwire is being extracted from the Data Stream.
H- RATE Thumbwheel selects the group data rate.
MD-1026 GM

7. CECOM LAR Tropo Operation Course
Group Rate Settings
0 OFF
1 72
This Setting is found on each DPHS A CCA. Setting will be set to input Data Rate. All unused MODEMS will be set to 0 (Zero)
MD-1026 GM

8. CECOM LAR Tropo Operation Course
C&I
A- Group 1-4- Multi-pin connectors, these are the NRZ BAL input/output going to the BBPP.
B- LINE SIGNAL- BNC Connectors, these are the 4 group outputs OUT 1-4 (CDI) to the Roadside Entry Panels.
C- LINE SIGNAL- BNC Connectors, these are the 4 group inputs IN 1-4 (CDI) from the Roadside Entry Panels.
D- TO ROA- These multi-pin connectors are not used. They GROUP 1-4 are for a Fiber Optic Upgrade, which was planned, but since has been dropped.
E- POWER- 115 V AC input power.
F- GND- External Ground connector
G- ORDERWIRE- These connectors route the Orderwire as described in the Transmit section.
H- STATION CLK AND ALARM- Provides Station Clock derived from CDI input.
MD-1026 GM

9. CECOM LAR Tropo Operation Course
Summary- MD-1026
Contains 4 Group Modems
Converts CDI to NRZ and vice versa
Processes and Routes Orderwire Signals show I/O
Summarize MD-1026
MD-1026 GM