ZyXEL Communications U-1496 series User Manual page 91

This command causes the DCE to produce DTMF and other tones.
The tone generation string shall consist of elements in a list with each element separated by
commas. Each element can be:
1) A single ASCII character in the set, 0-9, A-D, #, and *. The DCE shall interpret the ASCII
character as a DTMF digit with a duration given by the AT+VBT command.
2) Three numbers separated by commas and enclosed in square brackets. The DCE shall
interpret the first and the second number as the frequencies of the dual tone, and the third one
as the duration of the tone.
The frequency range is from 200 Hz to 3300 Hz, a frequency of zero means silence. The
range of the duration is from 0 to 255 in units of 0.1 second.
3) A single ASCII character and a number, separated by commas and enclosed in curly
braces. The DCE should interpret the ASCII character as a DTMF digit, and the number as the
duration of the tone.
AT+VTS=?
This command causes the DCE to report the allowable tone string elements. The response
is as follows:
(0,200-3300),(0,200-3300),0-9,A-D,*,#
OK
with <CR><LF> between each line.
AT+VTX
This command causes the DCE to start the voice transmission process.
The DCE begins the voice transmit mode by returning the CONNECT result code to the
DTE. After this report, the DCE accepts <DLE> shielded Voice data from the DTE.
The DTE can abort the voice transmit state by sending a <DLE><ETX> character pair to the
DCE. On termination of the voice transmit state, the DCE will send the VCON result code.
<DLE> SHIELDED CODES
In voice transmit/receive mode, BYSYNC protocol should be applied to the data stream
to/from DCE. During this period, commands and responses will be in <DLE> shielded form. The
supported <DLE> shielded codes are as follows (all <DLE> shield codes are case sensitive):
Commands:
<DLE><ETX>: terminate transmission process.
Responses:
<DLE>0: DTMF '0' received