| 1 |
62 |
marcus.erl |
$Id: README.audio,v 1.8 1999/07/11 17:17:29 armin Exp $
|
| 2 |
|
|
|
| 3 |
|
|
ISDN subsystem for Linux.
|
| 4 |
|
|
Description of audio mode.
|
| 5 |
|
|
|
| 6 |
|
|
When enabled during kernel configuration, the tty emulator of the ISDN
|
| 7 |
|
|
subsystem is capable of a reduced set of commands to support audio.
|
| 8 |
|
|
This document describes the commands supported and the format of
|
| 9 |
|
|
audio data.
|
| 10 |
|
|
|
| 11 |
|
|
Commands for enabling/disabling audio mode:
|
| 12 |
|
|
|
| 13 |
|
|
AT+FCLASS=8 Enable audio mode.
|
| 14 |
|
|
This affects the following registers:
|
| 15 |
|
|
S18: Bits 0 and 2 are set.
|
| 16 |
|
|
S16: Set to 48 and any further change to
|
| 17 |
|
|
larger values is blocked.
|
| 18 |
|
|
AT+FCLASS=0 Disable audio mode.
|
| 19 |
|
|
Register 18 is set to 4.
|
| 20 |
|
|
AT+FCLASS=? Show possible modes.
|
| 21 |
|
|
AT+FCLASS? Report current mode (0 or 8).
|
| 22 |
|
|
|
| 23 |
|
|
Commands supported in audio mode:
|
| 24 |
|
|
|
| 25 |
|
|
All audio mode commands have one of the following forms:
|
| 26 |
|
|
|
| 27 |
|
|
AT+Vxx? Show current setting.
|
| 28 |
|
|
AT+Vxx=? Show possible settings.
|
| 29 |
|
|
AT+Vxx=v Set simple parameter.
|
| 30 |
|
|
AT+Vxx=v,v ... Set complex parameter.
|
| 31 |
|
|
|
| 32 |
|
|
where xx is a two-character code and v are alphanumerical parameters.
|
| 33 |
|
|
The following commands are supported:
|
| 34 |
|
|
|
| 35 |
|
|
AT+VNH=x Auto hangup setting. NO EFFECT, supported
|
| 36 |
|
|
for compatibility only.
|
| 37 |
|
|
AT+VNH? Always reporting "1"
|
| 38 |
|
|
AT+VNH=? Always reporting "1"
|
| 39 |
|
|
|
| 40 |
|
|
AT+VIP Reset all audio parameters.
|
| 41 |
|
|
|
| 42 |
|
|
AT+VLS=x Line select. x is one of the following:
|
| 43 |
|
|
|
| 44 |
|
|
2 = Phone line.
|
| 45 |
|
|
AT+VLS=? Always reporting "0,2"
|
| 46 |
|
|
AT+VLS? Show current line.
|
| 47 |
|
|
|
| 48 |
|
|
AT+VRX Start recording. Emulator responds with
|
| 49 |
|
|
CONNECT and starts sending audio data to
|
| 50 |
|
|
the application. See below for data format
|
| 51 |
|
|
|
| 52 |
|
|
AT+VSD=x,y Set silence-detection parameters.
|
| 53 |
|
|
Possible parameters:
|
| 54 |
|
|
x = 0 ... 31 sensitivity threshold level.
|
| 55 |
|
|
(default 0 , deactivated)
|
| 56 |
|
|
y = 0 ... 255 range of interval in units
|
| 57 |
|
|
of 0.1 second. (default 70)
|
| 58 |
|
|
AT+VSD=? Report possible parameters.
|
| 59 |
|
|
AT+VSD? Show current parameters.
|
| 60 |
|
|
|
| 61 |
|
|
AT+VDD=x,y Set DTMF-detection parameters.
|
| 62 |
|
|
Only possible if online and during this connection.
|
| 63 |
|
|
Possible parameters:
|
| 64 |
|
|
x = 0 ... 15 sensitivity threshold level.
|
| 65 |
|
|
(default 0 , I4L soft-decode)
|
| 66 |
|
|
(1-15 soft-decode off, hardware on)
|
| 67 |
|
|
y = 0 ... 255 tone duration in units of 5ms.
|
| 68 |
|
|
Not for I4L soft decode (default 8, 40ms)
|
| 69 |
|
|
AT+VDD=? Report possible parameters.
|
| 70 |
|
|
AT+VDD? Show current parameters.
|
| 71 |
|
|
|
| 72 |
|
|
AT+VSM=x Select audio data format.
|
| 73 |
|
|
Possible parameters:
|
| 74 |
|
|
2 = ADPCM-2
|
| 75 |
|
|
3 = ADPCM-3
|
| 76 |
|
|
4 = ADPCM-4
|
| 77 |
|
|
5 = aLAW
|
| 78 |
|
|
6 = uLAW
|
| 79 |
|
|
AT+VSM=? Show possible audio formats.
|
| 80 |
|
|
|
| 81 |
|
|
AT+VTX Start audio playback. Emulator responds
|
| 82 |
|
|
with CONNECT and starts sending audio data
|
| 83 |
|
|
received from the application via phone line.
|
| 84 |
|
|
General behavior and description of data formats/protocol.
|
| 85 |
|
|
when a connection is made:
|
| 86 |
|
|
|
| 87 |
|
|
On incoming calls, if the application responds to a RING
|
| 88 |
|
|
with ATA, depending on the calling service, the emulator
|
| 89 |
|
|
responds with either CONNECT (data call) or VCON (voice call).
|
| 90 |
|
|
|
| 91 |
|
|
On outgoing voice calls, the emulator responds with VCON
|
| 92 |
|
|
upon connection setup.
|
| 93 |
|
|
|
| 94 |
|
|
Audio recording.
|
| 95 |
|
|
|
| 96 |
|
|
When receiving audio data, a kind of bisync protocol is used.
|
| 97 |
|
|
Upon AT+VRX command, the emulator responds with CONNECT, and
|
| 98 |
|
|
starts sending audio data to the application. There are several
|
| 99 |
|
|
escape sequences defined, all using DLE (0x10) as Escape char:
|
| 100 |
|
|
|
| 101 |
|
|
End of audio data. (i.e. caused by a
|
| 102 |
|
|
hangup of the remote side) Emulator stops
|
| 103 |
|
|
recording, responding with VCON.
|
| 104 |
|
|
Abort recording, (send by appl.) Emulator
|
| 105 |
|
|
stops recording, sends DLE,ETX.
|
| 106 |
|
|
Escape sequence for DLE in data stream.
|
| 107 |
|
|
0 Touchtone "0" received.
|
| 108 |
|
|
...
|
| 109 |
|
|
9 Touchtone "9" received.
|
| 110 |
|
|
# Touchtone "#" received.
|
| 111 |
|
|
* Touchtone "*" received.
|
| 112 |
|
|
A Touchtone "A" received.
|
| 113 |
|
|
B Touchtone "B" received.
|
| 114 |
|
|
C Touchtone "C" received.
|
| 115 |
|
|
D Touchtone "D" received.
|
| 116 |
|
|
|
| 117 |
|
|
q quiet. Silence detected after non-silence.
|
| 118 |
|
|
s silence. Silence detected from the
|
| 119 |
|
|
start of recording.
|
| 120 |
|
|
|
| 121 |
|
|
Currently unsupported DLE sequences:
|
| 122 |
|
|
|
| 123 |
|
|
c FAX calling tone received.
|
| 124 |
|
|
b busy tone received.
|
| 125 |
|
|
|
| 126 |
|
|
Audio playback.
|
| 127 |
|
|
|
| 128 |
|
|
When sending audio data, upon AT+VTX command, emulator responds with
|
| 129 |
|
|
CONNECT, and starts transferring data from application to the phone line.
|
| 130 |
|
|
The same DLE sequences apply to this mode.
|
| 131 |
|
|
|
| 132 |
|
|
Full-Duplex-Audio:
|
| 133 |
|
|
|
| 134 |
|
|
When _both_ commands for recording and playback are given in _one_
|
| 135 |
|
|
AT-command-line (i.e.: "AT+VTX+VRX"), full-duplex-mode is selected.
|
| 136 |
|
|
In this mode, the only way to stop recording is sending
|
| 137 |
|
|
and the only way to stop playback is to send .
|
| 138 |
|
|
|
