AudioCodes Mediant 500 E-SBC User Manual page 306

Parameter
Web: Fax Signaling Method
CLI: fax-sig-method
[IpProfile_IsFaxUsed]
Web: Remote RTP Base UDP Port
CLI: remote-base-udp-port
[IpProfile_RemoteBaseUDPPort]
User's Manual
Configuring Coder Groups on page 296).
Defines the SIP signaling method for establishing and
transmitting a fax session when the device detects a fax.

[0] No Fax = (Default) No fax negotiation using SIP
signaling. The fax transport method is according to the
FaxTransportMode parameter.

[1] T.38 Relay = Initiates T.38 fax relay.

[2] G.711 Transport = Initiates fax/modem using the
coder G.711 A-law/Mu-law with adaptations (see Note
below).

[3] Fax Fallback = Initiates T.38 fax relay. If the T.38
negotiation fails, the device re-initiates a fax session
using the coder G.711 A-law/ -law with adaptations (see
the Note below).
Notes:

Fax adaptations (for options 2 and 3):

Echo Canceller = On

Silence Compression = Off

Echo Canceller Non-Linear Processor Mode = Off

Dynamic Jitter Buffer Minimum Delay = 40

Dynamic Jitter Buffer Optimization Factor = 13

If the device initiates a fax session using G.711 (option 2
or 3), a 'gpmd' attribute is added to the SDP in the
following format:

For A-law: 'a=gpmd:8 vbd=yes;ecan=on'

For Mu-law: 'a=gpmd:0 vbd=yes;ecan=on'

When this parameter is set to 1, 2, or 3, the parameter
FaxTransportMode is ignored.

When this parameter is set to 0, T.38 might still be used
without the control protocol's involvement. To completely
disable T.38, set FaxTransportMode to a value other than
1.

For more information on fax transport methods, see
Fax/Modem Transport Modes on page 159.

The corresponding global parameter is IsFaxUsed.
Defines the lower boundary of the UDP port used for RTP,
RTCP (RTP port + 1) and T.38 (RTP port + 2). For example,
if the Base UDP Port is set to 6000, then one channel may
use the ports RTP 6000, RTCP 6001, and T.38 6002, while
another channel may use RTP 6010, RTCP 6011, and T.38
6012, and so on. For more information on determining the
port range, see Configuring RTP Base UDP Port on page
176.
The range of possible UDP ports is 6,000 to 65,535. The
default base UDP port is 6000.
Notes:

For this parameter to take effect, a device reset is
required.

If you set this parameter to a value that is not a factor of
10, the following message is generated: "invalid local
RTP port".

The UDP ports are allocated randomly to channels.
306
Mediant 500 E-SBC
Description
Document #: LTRT-10427