ISD-T360SB Datasheet, PDF (55/109 Pages) List of Unclassifed Manufacturers – VoiceDSP Digital Speech Processor with Master/Slave, Full-Duplex Speakerphone, Multiple Flash and ARAM/DRAM Support

2—SOFTWARE
ISD-T360SB
SPEAKERPHONE TERMINOLOGY
Send Path
The signal path from the microphone (near-end
speaker) to the line (far-end listener). The micro-
phone is the input port, and line-out is the output
port of this signal path.
Receive Path
The signal path from the line (far-end speaker) to
the loudspeaker (near-end listener). The line-in is
the input port, and the speaker is the output port
for this signal path.
Hold
During Hold mode interrupts from both codecs
are stopped. Neither side can hear each other.
Restart
In Restart mode the speakerphone re-initializes it-
self to the last speakerphone mode (full-duplex,
transparent or mute). This mode should be used
to resume the speakerphone operation after
Hold mode or when there is a significant change
in the environmental conditions (e.g., parallel
pickup) that may affect the speakerphone qual-
ity.
AEC
Acoustic Echo Controller. The part in the speak-
erphone algorithm that controls the echo in the
sendpath.
EEC
Electric Echo Controller. The part in the speaker-
phone algorithm that controls the echo in the re-
ceive path.
SPEAKERPHONE MODES OF OPERATION
Full-Duplex (ON)
The speakerphone works in full-duplex mode,
meaning both parties can speak and hear each
other simultaneously. In this mode both the
acoustic and electric echo controllers are ac-
tive. The VoiceDSP processor tone detectors are
not active in this mode.
Transparent
While in Transparent mode, the speakerphone
works in full-duplex mode but without echo can-
cellation.
Samples from the microphone are transferred to
the line, and samples from the line are trans-
ferred to the speaker, with no processing. This
mode should be used only for tuning and testing
the system.
Listen
In Listen mode the line is audible on the speaker,
and the processor tone detectors are active.
During Listen mode, dialing with the GT com-
mand and call progress is possible, since the
busy and dial tone detectors are active.
The following pseudo-code demonstrates how
to make a call from speakerphone mode:
Mute
In this mode of operation, the speakerphone
generates silence to the line. The near-end listen-
er can hear the far-end speaker but not vice ver-
sa. Tone detectors are not active.
ISD
2-15