Comtech EF Data SDM-100A - Manual (Page 135)

SDM-100A Satellite Modem Theory of Operation
Rev. 0 4–19
J1
11
24
+TT
-TT
TT
J2
5
6
37,38
31,32
SD
+5V
-5V
+S
-SD
14
2
21
23
20
DEMOD FAULT
-MC
+MC
MC
DF 15
13
16
7
14
RS
CS
MF MOD FAULT
+ST
RS
CS
25
12
5
4
15
9
17
+RT
-RT
-ST
+12V
RT
ST
33,34
10
8
11
12
35,36
RD
RR
-12V
+RD
-RD
16
3
8 -RR
GND
DM
GND
9
1,2
39,40
4
3
INTF1
INTF0
GND
-DM 6
1, 7
Figure 4-7. V.35 Interface
The clock selection is jumper selectable at JP1 on the front edge of the board.
• The NORMAL setting is used when standard specifications on clock and data
relationships exist.
• The INVERT mode is used when the incoming clock is inverted from the
standard clock and data relationship.
Data received by the modem is output on the Receive Data (RD) lines, while the
recovered clock is output on the Serial Clock Receive (SCR) lines.
• Receive Clock NORMAL mode should be selected for applications that require
the rising edge of the clock to occur in the middle of the data bit time.
• INVERT mode puts the falling edge of SCR in the middle of the data bit.
Note: This selection can be made from the front panel in the Configuration menu
or from a remote terminal.