Specifications

SDM-300L3 Satellite Modem Revision 0

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.

ABLE 5-3. IBS PARAMETER SETTINGS

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.