Comtech EF Data SDM-300L3 - Manual (Page 203)

SDM-300L3 Satellite Modem Revision 1
Modem Types MN/SDM300L3.IOM
5–3
5.3 IBS Operation
To operate the modem in the IBS configuration, the following cards shall be installed in the
modem:
• Overhead G.703/IDR/IBS/ASYNC/AUPC/D&I card
• 50-pin D relay adapter card
The IBS option is a FAST feature that shall be enabled using the front panel and the
Utility: Modem Type menu. Table 5-3 lists the parameters that are accessible once the IBS
modem type is enabled.
The IBS modem type is an open network application, primarily used for data circuits. IBS has a
variable overhead structure that is dependent on the transmitted data rate.
T ABLE 5-3. IBS P ARAMETER S ETTINGS
Parameter Front Panel Setting Reference Menu
Modem Type IBS (see Note ) Utility Modem Type
TX Data/Code Rate TX-V, QPSK 1/2, or 3/4 Configuration Modulator
TX-IF Output ON Configuration Demodulator
RX Data/Code Rate RX-V, QPSK 1/2, or 3/4 Configuration Demodulator
TX Clock Source TX Terrestrial, Internal, Ext. Reference Configuration Interface
Buffer Clock Source Satellite, TX Terrestrial, Internal, Ext.
Reference Configuration Interface
TX Coding Format AMI, B8ZS, or HDB3 Configuration Interface
RX Coding Format AMI, B8ZS, or HDB3 Configuration Interface
Note: This mode of operation is IESS-309 compliant for all modes with Viterbi coding = On and
Reed-Solomon = Off. It also is interoperable with EFD legacy equipment that is set to
Modem Type = IBS with RS = On (K/N = 112/126) or RS = Off.
5.3.1 309 IBS Operation
This mode is for IESS-309 (IBS) operation when Reed-Solomon is tuned On. Operation is the
same as outlined in Paragraph 5.3, except, Reed-Solomon is On and K/N = 201/219.
5.3.2 VSAT IBS Operation
This is for IESS-309 operation with No Overhead framing. Operation is the same as in Paragraph
5.3, except framing is tuned Off when RS = On and K/N = 201/219.