Transparent Modes; Voice Transparent Mode; Ppp Transparent Mode - Intracom netMod User Manual

User's Manual of netMod Network Termination Unit

Transparent Modes

For applications like voice or fax through the PC (with proper software running in the PC),
netMod transfers data transparently from the data port to the occupied B-Channel and vice
versa. Then the PC software processes these data.
The following types of transparent modes are available:

Voice Transparent Mode

In this mode the data received from the data interface are transparently transmitted
to the connected B-channel and vice versa. If no data are available from the data
interface, an audio pattern that corresponds to silence and depends on the coding
law used in the particular country is transmitted to the B-Channel. If this mode is
enabled, netMod will use the 3.1kHz audio bearer capability for outgoing data calls
and will accept incoming calls with speech and 3.1kHz audio bearer capability. This
means that you are able to answer a call or make one to a fax or to an analogue
telephone. The data that are received and transferred to the computer must be
handled by appropriate software.
You can enable audio transparent mode by writing to the S82-Register the value 76.

PPP Transparent Mode

In this mode the received and transmitted data are transferred from / to the data port
and the B-Channels in the same way as in the PPP protocol (HDLC framing with PPP
heading). The only difference is that these data will be transparently transferred by
netMod. Only CRC inspection is done in each packet. When an error is found, the
packet is rejected. netMod uses the unrestricted digital bearer capability for the
outgoing calls and does not accept incoming voice calls and 3.1kHz audio. The
transmitted and received data from / to the PC have to be processed through the
proper software.
You can activate the PPP transparent mode by writing to the S82-Register the value
78.
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