Intel MD566X - Manual (Page 94)

56K V.92 Data, Fax, and Voice Chipset
94 Intel Confidential Programmer’s Guide
+VSM=m
manufac-
turer-
specified
Compression Method Selection: This command contains four parameters that
specify the voice compression method, voice sampling rate, silence compression
sensitivity, and the degree of silence expansion. The DCE can support different
capabilities for each compression method.
m= <cml>, <vsr>, <scs>, <sel>
Defaults: m = 140, 8000, 0, 0
<cml> Compression Method: This parameter selects a voice compression
method. The DTE can obtain the label and a string constant identifier by using
the +VSM? command.
Range: <cml> = 0–2, 128, 129, 132, 140, 141
Default: <cml> = 140
<cml> = 0 LIN1: 8-bit Linear PCM (pulse code modulation) sampling using
twos-complement signed numbers
<cml> = 1 LIN2: 16-bit Linear PCM sampling using unsigned numbers
<cml> = 2 AD4: 4-bit Adaptive differential pulse code modulation
<cml> = 128 LIN1: 8-bit Linear PCM (pulse code modulation) sampling using
twos-complement signed numbers
<cml> = 129 LIN2: 16-bit Linear PCM sampling using unsigned numbers
<cml> = 132 AD4: 4-bit Adaptive differential pulse code modulation
<cml> = 140* CL1: 8-bit Intel A-law
<cml> = 141 AD3: 3-bit Adaptive differential pulse code modulation
<vsr> Sampling Rate: This parameter selects the DCE voice sampling/digitiz-
ing rate for the voice signal. The supported sampling rates are dependent on the
compression schemes used. Use the +VSM=? command to obtain supported
sampling rates.
Range: <vsr> = 4800, 7200, 8000, and 11025 samples/second
Default: <vsr> = 8000*
<scs> Silence Sensitivity: The function of this parameter depends on whether
the DTE is transmitting or receiving in voice mode. The DTE can modify the si-
lence expansion using the <sel> parameter. When transmitting voice, a non-zero
value of this parameter informs the DCE that the data stream was recorded with
silence compression.
Table 6-1. Voice Mode Command Descriptions (Continued)
<vsr>
(samples/second)
Comments
4800 Default used by previous legacy modems
7200
8000
Used by some bulletin boards
9600
11025 Used by many Windows
∗
.WAV files