AudioCodes Mediant 600 - DTMF and Hook-Flash Parameters

SIP User's Manual 644 Document #: LTRT-83310
Mediant 600 & Mediant 1000
Parameter Description
set to 1 (T.38 Relay) or 3 (Fax Fallback).
[T38FaxSessionImmediate
Start]
Enables fax transmission of T.38 “no-
signal” packets to the terminating
fax machine.
 [0] Disable (default)
 [1] Enable
This is used for transmission from fax machines (connected to the
device) located inside a Network Address Translation (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 fax fails.
To overcome this, the device sends No-Op (“no-signal”) packets to
open a pinhole in the NAT for the answering fax machine. The
originating fax does not wait for an answer, but immediately starts
sending T.38 packets to the terminating fax machine.
Note: To enable No-Op packet transmission, use the NoOpEnable
and NoOpInterval parameters.
A.12.2 DTMF and Hook-Flash Parameters
The DTMF and hook-flash parameters are described in the table below.
Table A-38: DTMF and Hook-Flash Parameters
Parameter Description
Hook-Flash Parameters
Web/EMS: Hook-Flash Code
[HookFlashCode]
For analog interfaces: Defines the digit pattern that when received
from the Tel side, indicates a Hook Flash event. For digital interfaces:
Defines the digit pattern used by the PBX to indicate a Hook Flash
event. When this pattern is detected from the Tel side, the device
responds as if a Hook Flash event has occurred and sends a SIP
INFO message if the HookFlashOption parameter is set to 1, 5, 6, or 7
(indicating a Hook Flash). If configured and a Hook Flash indication is
received from the IP side, the device generates this pattern to the Tel
side.
The valid range is a 25-character string. The default is a null string.
Note: This parameter can also be configured per Tel Profile, using the
TelProfile parameter.
Web/EMS: Hook-Flash
Option
[HookFlashOption]
Determines the hook-flash transport type (i.e., method by which hook-
flash is sent and received). For digital interfaces (E1/T1): This feature
is applicable only if the HookFlashCode parameter is configured.
 [0] Not Supported = Hook-Flash indication is not sent (default).
 [1] INFO = Sends proprietary INFO message (Broadsoft) with
Hook-Flash indication. The device sends the INFO message as
follows:
Content-Type: application/broadsoft; version=1.0
Content-Length: 17
event flashhook
 [4] RFC 2833 = This option is currently not supported.