Comtech EF Data SDM-300A - Manual (Page 338)

SDM-300A Satellite Modem Revision 6
Troubleshooting MN/SDM300A.IOM
18–2
18.2 Interface Checkout
Use the following procedure and the test setup in Figure 18-1 to inspect the interface.
Figure 18-1. Fault Isolation Test Setup
1. Connect a BER test set to the appropriate modem data connector as shown in Refer to
Figure 18-1 Chapter 5 for external modem connections.
2. Set up the modem for baseband loopback operation by using the Configuration:
Interface front panel menu (Chapter 5). The modem will run error free. Refer to
Chapter 3 for a block diagram of the baseband loopback operation.
3. Change the modem from baseband loopback to interface loopback operation by using
the Configuration: Interface front panel menu (Chapter 5). The modem will run error
free. Refer to Chapter 5 for a block diagram of the interface loopback operation.