Fax And Modem Capabilities; Fax/Modem Operating Modes - AudioCodes Mediant 2000 User Manual

Sending DTMF digits (in RTP packets) as part of the audio stream (DTMF Relay
is disabled): This method is typically used with G.711 coders; with other low-bit rate
(LBR) coders, the quality of the DTMF digits is reduced. To enable this mode, define
the following:
•
RxDTMFOption = 0 (ini file); 'Declare RFC 2833 in SDP' field = 'No' (Web
interface -- refer to ''DTMF & Dialing Parameters'' on page 147)
•
TxDTMFOption = 0 (ini file); '1
interface -- refer to ''DTMF & Dialing Parameters'' on page 147)
•
DTMFTransportType = 2 (DTMF Transport Type = Transparent DTMF)
Using INFO message according to Korea mode: DTMF digits are carried to the
remote side in INFO messages. To enable this mode, define the following:
•
RxDTMFOption = 0 (ini file); 'Declare RFC 2833 in SDP' field = 'No' (Web
interface -- refer to ''DTMF & Dialing Parameters'' on page 147)
•
TxDTMFOption = 3 (ini file); '1
interface -- refer to ''DTMF & Dialing Parameters'' on page 147)
Note that in this mode, DTMF digits are erased from the audio stream
(DTMFTransportType is automatically set to 0 (DTMF Mute)).
Notes:
The following parameters affect the way the device handles the DTMF digits:
TxDTMFOption, RxDTMFOption, and RFC2833PayloadType (described in ''DTMF &
Dialing Parameters'' on page 147)
MGCPDTMFDetectionPoint, DTMFVolume, DTMFTransportType, DTMFDigitLength,
and DTMFInterDigitInterval (refer to ''Channel Parameters'' on page 324)
7.5

Fax and Modem Capabilities

7.5.1

Fax/Modem Operating Modes

The device supports two modes of operations:
Fax / modem negotiation that isn't performed during the establishment of the call.
VBD mode for V.152 implementation (refer to ''Supporting V.152 Implementation'' on
page 357): fax / modem capabilities are negotiated between the device and the remote
endpoint at the establishment of the call. During a call, when a fax / modem signal is
detected, transition from voice to VBD (or T.38) is automatically performed and no
additional SIP signaling is required. If negotiation fails (i.e., no match is achieved for
any of the transport capabilities), fallback to existing logic occurs (according to the
parameter IsFaxUsed).
SIP User's Manual
•
The device is always ready to receive DTMF packets over IP in all
possible transport modes: INFO messages, NOTIFY, and RFC 2833 (in
proper payload type) or as part of the audio stream.
•
To exclude RFC 2833 Telephony event parameter from the device's
SDP, set RxDTMFOption to 0 in the ini file.
to 5 Tx DTMF Option' field = 'Disable' (Web
st th
to 5 Tx DTMF Option' field = 'INFO (Korea)' (Web
st th
350
Mediant 2000
Document #: LTRT-68808