Comtech EF Data SLM-7650 Installation And Operation Manual page 46

SLM-7650 Satellite Modem
Operation
Menu Item
B-BAND LOOPBACK
(Test Mode Configuration)
LOOP TIMING
TX CODING FORMAT
AMI, B6ZS, B8ZS, or
HDB3
RX CODING FORMAT
AMI, B6ZS, B8ZS, or
HDB3
TX DATA Alarm
RX DATA ALARM
TX 2047 PATTERN
(Test Mode Configuration)
Programs the modem for baseband loopback operation.
Baseband loop back will turn around the data and clock to the user at the terrestrial
interface of the modem. This is a bi-directional loop so the data and clock over the
satellite is also turned around. Refer to Figure 5-10 for a block diagram of baseband
loopback operation.
On entry, the current status is displayed. Press an arrow key to make the selection.
Press [ENTER] to execute the change.
Loop timing ON will phase lock the SCT internal clock to the recovered satellite clock
of the decoder. This is used at the Slave end of a Satellite link to clock the data in and
out of the modem using the clock from the distant end of the link. Selecting Loop
timing ON will cause the SCT (INT) to change to SCT (Loop) and the SCT PLL REF to
display RX Loop. Turn loop timing OFF to make another choice at the SCT PLL REF
menu.
On entry, the current status is displayed. Press an arrow key to make the selection.
Press [ENTER] to execute the change.
Programs the transmitter for AMI, B6ZS, B8ZS, or HDB3 coding of the baseband data.
On entry, the current coding format is displayed. Press an arrow key to make the
selection. Press [ENTER] to execute the change.
Note: This menu is only available when G.703 interface is installed.
Programs the receiver for AMI, B6ZS, B8ZS, or HDB3 coding.
On entry, the current coding format is displayed. Press an arrow key to make the
selection. Press [ENTER] to execute the change.
Note: This menu is only available when G.703 interface is installed.
Transmit data fault. Press an arrow key to select one of the following modes:
None: The transmit interface fault Data/AIS is not activated.
Alarm Indication Signal (AIS): This is also commonly referred to as All Ones. The
M&C will produce an alarm if the customer is inputting data that is all
ones.
Data: The M&C will produce an alarm if the Customer input data is missing (all
zeros or all ones).
On entry, the current TX data fault that is being monitored is displayed. Press an arrow
key to make the selection. Press [ENTER] to execute the change.
Receive data Alarm. Selects a receive interface alarm monitor of None, AIS, or Data.
The data monitored for RX data is coming from the satellite. Refer to TX DATA
ALARM for a description of function choices.
On entry, the current RX DATA ALARM that is being monitored is displayed. Press an
arrow key to make the selection. Press [ENTER] to execute the change.
Programs the modem to transmit a test pattern instead of the incoming data stream.
Selections are as follows:
NONE
2047 (compatible with a Fireberd BERT)
MIL-188 This is a modified 2047 pattern that is used to test the Data Source Sync
function of the modem. It has the maximum number of consecutive zeros
that the modem can handle when recovering the clock from the data
transitions.
On entry, the current status is displayed. Press an arrow key to make the selection.
Press [ENTER] to execute the change.
3-14
Specifications/usage
Revision 4
MN/SLM7650.IOM