US Robotics 56K USB Modem User Manual page 93

+VTR—Start Voice Transmission and Reception Process
Use this command to initiate full-duplex voice mode* in the DCE. In this mode, the DTE selects the analog
source and sink through the +VLS command; the selections can be microphone and speaker or GSTN.
The DCE is not required to perform any acoustic echo cancellation or line echo cancellation.
Result codes:
• CONNECT if full-duplex voice mode is initiated.
• ERROR if the DCE is not connected to at least one off-hook duplex PSTN line or one duplex non-
PSTN device.
+VTS=<string>—DTMF and Tone Generation in Voice Mode
Use this command to produce a sequence of DTMF tones (or other tones, such as dial tone, busy, silence,
etc.) as specified in the string parameter. String parameters are made up of a sequence of elements
separated by commas. If the string does not supply a duration for a particular tone, then the DCE uses the
duration designated by the +VTD command. The command can also generate a hook flash, +VTS=!.
Result codes:
• OK if <string> is valid (see Table 201).
• ERROR if <sting> is not valid.
* See ITU-T Recommendation V.253 for further details on the voice states.
Table 200. +VTS Extended Syntax Commands
Command
+VTS=<string>
+VTD=?
Table 201. String Elements
String Elements
A single character
A bracketed group []
A curly bracketed group {}
* The string definition provided in this text is a excerpt from the detailed definition provided in ITU-T Recommendation V.253 (02/98).
Refer to Section 10.1.5.1.1 for a full description of the <string> parsing.
† The tone specified in the bracketed group in a numerical value between 300 and 3300.
Generates DTMF tones according to the <string> parameter.
Displays the range of supported tones and duration.
*
The valid single characters are 0—9, #, *, !, and A—D. This element always
uses the default duration specified by the +VTD command.
A bracketed group has three components. It is used to generate a dual tone.
The first component is the first tone
is the second tone
the tones. The duration is specified in 0.01 s intervals. If one of the tone
parameters is missing, its value is defaulted to 0 and that tone is not gener-
ated.
A curly bracketed group has two components. The first component is a DTMF
tone or hookflash character(!). The second component is the tone duration.
The duration of the tone is specified in 0.01 s intervals.
Function
Description
†
in the dual tone. The second component
†
in the dual tone. The third component is the duration of
56K USB Modem
User Guide
Command Reference - 87