Rockwell RCV144ACx, Command Reference Manual

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AT Command Reference Manual
7-8 1048
7.2.6 Voice Record
To effect recording of a message received via a handset or microphone, the DTE must configure the modem for Voice Mode
(#CLS=8), and select the proper relay setup (#VLS) to instruct the modem whether to use the auxiliary device. The modem
responds to the #VLS command by issuing a relay activate command to select the input device. When a device other than
the telephone line is selected, the modem immediately enters Online Voice Command Mode (indicated by VCON). DTMF
detection is therefore enabled as soon as the DTE selects the device, such as a handset, although the user still needs to
physically pick up the telephone and “press buttons.” Even if the DTE has not entered Voice Receive or Transmit Modes
(#VTX or #VRX), these DTMF tones are delivered via shielded codes identically to when a physical telephone connection
exists but the DTE has not yet commanded receive or transmit.
When the DTE decides to record the message, it issues the #VRX command and upon command receipt, the modem
immediately switches to Voice Receive Mode. Since the microphone or handset is switched in, the modem immediately
issues the CONNECT message indicating that the modem has switched to Voice Receive Mode and is beginning the
transfer of ADPCM voice or PCM audio data as well as shielded DTMF tones, and other tones and statuses.
In this recording state, the modem (if so configured) monitors for line silence. If the #VSP period expires, the modem sends
the <DLE>q or <DLE>s code to the DTE.
Recording can be canceled only via two events:
1. The DTE sends any character to the modem. This is the key abort, and is the normal method of terminating the receive
mode.
2. The S30 Disconnect Inactivity timer expires, which is generally an undesired event.
7.2.7 Voice Playback
To effect playback of a message recorded via a handset or microphone, or of a message recorded during a voice call, the
DTE must configure the modem for Voice Mode (#CLS=8) and select the proper relay setup (#VLS) to instruct the modem
whether to use the handset or speaker. The modem responds to the #VLS command by issuing a relay activate command to
select the input device. The hardware must provide a means of selecting a handset and/or microphone instead of the
telephone line, as this input device. When a device other that the telephone line is selected, the modem immediately enters
Online Voice Command Mode (indicated by VCON). DTMF detection is thus enabled as soon as the DTE selects the device,
such as a handset, although the user still needs to physically pick up the telephone before he can issue DTMF tones. Once
selected, however, the user can indeed pick up the telephone and “press buttons.” Even if the DTE has not entered Voice
Receive or Transmit Modes (#VTX or #VRX), these DTMF tones are delivered via shielded codes, identically to when a
physical telephone connection exists but the DTE has not yet commanded receive nor transmit.
When the DTE decides to play the message, it issues the #VTX command, and the modem immediately switches to Voice
Transmit Mode. Since the speaker or handset is already switched in, the modem immediately issues the CONNECT
message indicating that the modem is in Voice Transmit Mode and is expecting voice data from the DTE.
A subsequent <DLE><ETX> has to be issued to switch back to Online Voice Command Mode.
Volume Adjustment During Record
The record volume is adjusted automatically by an automatic gain control (AGC) circuit (for V.34 and ACF/SP products).
Volume Adjustment During Playback
The playback volume of the headphone and speaker outputs and handset can be adjusted by the #TL command (Section
7.3.2).