Comtech EF Data SDM-300L3 - Manual (Page 276)

SDM-300L3 Satellite Modem Revision 1
Open Network Operations MN/SDM300L3.IOM
10–18
10.5 2xADPCM Voice in 64 kbps IBS
2xADPCM Voice in 64 kbps IBS operation is an optional feature available with the IBS
option or the IDR option. This mode is a hybrid cross between IDR and IBS where the
two 32 kbps ADPCM voice channels that are part of the IDR ESC circuits are mapped
into a single 64 kbps IBS channel to provide two full-duplex voice channels.
Adjustment of the voice channel levels is made the same as in IDR operation. When this
mode is active the two voice channels completely use the 64 kbps IBS channel and the
only data channel provided is the IBS ESC overhead channel that operates in 1/2000 x 64
kbps and described in the IBS section.
To operate in this mode (refer to Chapter 4):
• Set the Modem Type to IBS mode.
• Place the modem in the IBS Audio mode. (See IBS TX and/or RX ESC Type to
2-32k Audio menu, located under the Utility: Interface menu.)
• Adjustment of the voice channel levels is made from the Service Channel Adjust
(under the Configuration: Interface menu).