AudioCodes Mediant 500 E-SBC, User Manual

Page: 796 / 920

User's Manual 796 Document #: LTRT-10437
Mediant 500 E-SBC
Parameter Description
Web/EMS: T.38 Max Datagram
Size
CLI: t38-mx-datagram-sz
[T38MaxDatagramSize]
Defines the maximum size of a T.38 datagram that the device
can receive. This value is included in the outgoing SDP when
T.38 is used.
The valid range is 120 to 600. The default is 560.
Web/EMS: T38 Fax Max Buffer
CLI: t38-fax-mx-buff
[T38FaxMaxBufferSize]
Defines the maximum size (in bytes) of the device's T.38 buffer.
This value is included in the outgoing SDP when T.38 is used
for fax relay over IP.
The valid range is 500 to 3000. The default is 3000.
Web: Detect Fax on Answer Tone
EMS: Enables Detection of FAX on
Answer Tone
CLI: det-fax-on-ans-tone
[DetFaxOnAnswerTone]
Determines when the device initiates a T.38 session for fax
transmission.

[0] Initiate T.38 on Preamble = (Default) The device to which
the called fax is connected initiates a T.38 session on
receiving HDLC Preamble signal from the fax.

[1] Initiate T.38 on CED = The device to which the called fax
is connected initiates a T.38 session on receiving a CED
answer tone from the fax. This option can only be used to
relay fax signals, as the device sends T.38 Re-INVITE on
detection of any fax/modem Answer tone (2100 Hz,
amplitude modulated 2100 Hz, or 2100 Hz with phase
reversals). The modem signal fails when using T.38 for fax
relay.
Note: This parameters is applicable only if the IsFaxUsed
parameter is set to 1 (T.38 Relay) or 3 (Fax Fallback).
Web: CED Transfer Mode
[CEDTransferMode] Defines the method for sending fax/modem CED (answering)
tones.

[0] Fax Relay or VBD = (Default) The device transfers the
CED tone in Relay mode and starts the fax session
immediately.

[1] Voice Mode or VBD = The device transfers the CED tone
in either Voice or Bypass mode and starts the fax session on
V21 preamble.

[2] RFC 4733 Blocking RTP VBD = The device transfers the
CED tone in RFC 2833. This is applicable only to V.150.1
modem relay and fax bypass.

[3] RFC 4733 Along with RTP VBD = The device transfers
the CED tone in RFC 2833 and bypass, in parallel. For
combined V.150.1 modem relay and fax relay, use this
option.
Web: T.38 Fax Session
CLI: t38-sess-imm-strt
[T38FaxSessionImmediateStart]
Enables fax transmission of T.38 "no-signal" packets to the
terminating fax machine.

[0] Disable (default)

[1] Immediate Start on Fax = Device activates T.38 fax relay
upon receipt of a re-INVITE with T.38 only in the SDP.

[2] Immediate Start on Fax & Voice = Device activates T.38
fax relay upon receipt of a re-INVITE with T.38 and audio
media in the SDP.
This parameter is used for transmission from fax machines
connected to the device and located inside a NAT. Generally,
the firewall blocks T.38 (and other) packets received from the
WAN, unless the device behind NAT sends at least one IP
packet from the LAN to the WAN through the firewall. If the
firewall blocks T.38 packets sent from the termination IP fax, the