AudioCodes Mediant 3000, User Manual

Page: 180 / 872

User's Manual 180 Document #: LTRT-89729
Mediant 3000
a. Set the 'Profile Number' parameter (V1501AllocationProfile) to the amount of
DSP channels allocated for regular voice and V.150.1 Modem Relay capability.
Once the V.150.1 session has been negotiated and activated by SIP, a Modem
Relay DSP channel is allocated alongside the existing allocated voice DSP
channel. The DSP Modem Relay channel is responsible for the entire V.150.1
part of the call. The table below lists the currently supported DSP allocation
options:
DSP Allocation Options for V.150.1 Modem Relay
Blade Profile Number
Value
Number of Voice
Channels
Number of Modem
Channels
TP-8410 16 E1/21 T1 2 336 48
TP-8410 16 E1/21 T1 4 168 96
TP-8410 11 840 264
TP-6310 11 840 264
Notes:
•
The TP-8410 16 E1/21 T1 blade provides 6 DSPs, supporting up to 21
DS1 spans. The TP-8410 and TP-6310 blades provide 21 DSPs,
supporting up to 84 DS1 spans.
•
The Number Of Voice Channels column represents channel density
when the blade supports SRTP.
a. Set the 'SSE Payload Type Rx' parameter to the V.150.1 SSE payload type that
the device uses when it offers the SDP.
b. Set the 'SSE Redundancy Depth' parameter to the number of sent SSE
redundant packets. This parameter is important in case of network impairments.
c. For additional V.150.1 related parameters, see 'Fax and Modem Parameters' on
page
739 .
13.2.5 Simultaneous Negotiation of Fax (T.38) and Modem (V.150.1)
Relay
The device can negotiate fax relay (T.38) and modem relay (V.150.1) sessions in the
same, already established call channel. Fax relay sessions require bypass answering tone
(CED) while modem relay requires RFC 2833 answering tone. As the device is not always
aware at the start of the session whether the answering tone is fax or modem, it uses both
methods for CED tone transfer and sends both answering tone types. Only when the
answering tone is detected, does the device send the fax or modem.
To support this functionality, you need to configure a Coders Group (in the Coders Group
table - see 'Configuring Coder Groups' on page
260 ) t
hat includes the T.38, V.150, and
G.711/VBD coders
.
13.2.6 V.152 Support
The device supports the ITU-T recommendation V.152 (Procedures for Supporting Voice-
Band Data over IP Networks). Voice-band data (VBD) is the transport of modem, facsimile,
and text telephony signals over a voice channel of a packet network with a codec
appropriate for such signals.