AudioCodes MediaPack 114 Bedienungsanleitung PDF herunterladen (Seite 324)

SIP User's Manual 324 Document #: LTRT-65411

MediaPack Series

After a few seconds upon detection of fax V.21 preamble or super G3 fax signals, the

device sends a second Re-INVITE enabling the echo canceller (the echo canceller is

disabled only on modem transmission).

A ‘gpmd’ attribute is added to the SDP according to the following format:

 For G.711A-law: a=gpmd:0 vbd=yes;ecan=on (or off, for modems)

 For G.711 µ-law: a=gpmd:8 vbd=yes;ecan=on (or off for modems)

The parameters FaxTransportMode and VxxModemTransportType are ignored and

automatically set to the mode called ‘transparent with events’.

To configure fax / modem transparent mode, set IsFaxUsed to 2.

7.3.2.7 Fax Fallback

In this mode, when the terminating device detects a fax signal, it sends a Re-INVITE

message to the originating device with T.38. If the remote device doesn’t support T.38

(replies with SIP response 415 'Media Not Supported'), the device sends a new Re-INVITE

with G.711 VBD with the following adaptations:

 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

When the device initiates a fax session using G.711, a ‘gpmd’ attribute is added to the SDP

according to the following format:

 For G.711A-law: a=gpmd:0 vbd=yes;ecan=on

 For G.711 µ-law: a=gpmd:8 vbd=yes;ecan=on

In this mode, the parameter FaxTransportMode is ignored and automatically set to

‘transparent’.

To configure fax fallback mode, set IsFaxUsed to 3.

7.3.3 Supporting V.34 Faxes

Unlike T.30 fax machines, V.34 fax machines have no relay standard to transmit data over

IP to the remote side. Therefore, the device provides the following operation modes for

transporting V.34 fax data over the IP:

 Using bypass mechanism for V.34 fax transmission (refer to ''Using Bypass

Mechanism for V.34 Fax Transmission'' on page 325)

 Usi

ng relay mode, i.e., fallback to T.38 (refer to ''Using Relay mode for both T.30 and

V.34 faxes'' on page 325)

Usi

ng the ini file parameter V34FaxTransportType, you can determine whether to pass V.34

Fax-over-T.38 fallback to T.30, or use Bypass over the High Bit Rate coder (e.g. PCM A-

Law).

Note: The CNG detector is disabled (CNGDetectorMode = 0) in all the subsequent

examples.

1 2 ... 319 320 321 322 323 324 325 326 327 328 329 ... 389 390

Kommentare zu diesen Handbüchern

Keine Kommentare

AudioCodes MediaPack 114 Bedienungsanleitung Seite 324

Kommentare zu diesen Handbüchern

Verwandte Produkte und Handbücher für Gateways / Controller AudioCodes MediaPack 114