Comtech EF Data SDM-309B - Manual (Page 170)

Data Rates and Filters SDM-309B Satellite Modem
A–2 MN/U-SDM309B Rev. #
8. With a phillips screwdriver, remove the four (4) screws holding down the
daughter card. See Figure A-2 for location of the hardware.
9. Remove the daughter card (0698) from the demodulator.
10. Install the replacement daughter card (0698) so that J1 on the daughter card lines
up with J2 on the demodulator card and J2 on the daughter card lines up with J3
on the demodulator card and all four hold down screws line up. See Figure A-2.
!
CAUTION
If the filter is installed in the wrong position, damage will result on
the daughter card.
11. Reinstall the daughter board hold down screws (Figure A-2) and reinsert the
demodulator into the modem chassis.
12. Remove the M&C board and remove JP6 (Battery ON/OFF) for at least 10
seconds. Replace the battery jumper to the ON position and reinsert the M&C
card into the modem.
13. Turn on the power switch.
14. Go to the “Utility” menu on the front panel and program the time and day. Note:
The data/code rate assignment of a fixed rate filter in the “Utility” menu is
automatically read by the M&C when power is turned on. Also each daughter
card is labeled with the filter assignment (A, B, C, and D) and the associated
symbol rate. Example - the label for a 64KBPS, 7/8 rate, QPSK filter is 36.57.
15. Go to the “Config” menu on the front panel and select the TX and RX rate that is
desired and turn ON the RF output. The hardware change is complete.
1.2 Variable Rate Filters
1. Turn on the power switch.
2. Go to the “Utility” menu on the front panel and program the TXA, TXB, TXC,
TXD, RXA, RXB, RXC, and/or RXD to the new desired data/code rates. Refer
to the “Utility” menu of the Front Panel Operation in Chapter 3 for complete
programming details.
3. Go to the “Config” menu on the front panel and select the TX and RX rate that is
desired or select TXV and RXV and enter new desired data/code rates into the
menu and Press “Enter” to execute the change. Remember that you can only
select data rates up to and including 2048 Kpbs with a variable rate filter. Refer
to Table 6-2 for a list of the programmable data rates of the variable rate filters.
Enter the “Config MOD” menu and turn ON the RF output. The software change
is complete.