Technical data

ECM (Error Correction Mode) support

You can control ECM support via the FAX CLASS 2 AT-command set or via Global Dialogic® Diva® TTY

configuration options on page 73.

If you use global Diva TTY configuration options to enable ECM support, the Dialogic

Diva

Media Board will use

ECM mode for document transfer, if supported by the opposite side.

Diva Media Boards use their internal memory to store document data. They retrieve data for ECM re-

transmissions from this internal buffer (up to 64 Kbytes for every channel). This reduces the host CPU load and

increases the reliability of the fax transmission.

Document compression support

Dialogic

Diva

Media Boards use MR, MMR, T.6 fax document compression. In order to reduce transmission

time, Diva Media Boards select the best compression algorithm supported by the opposite side. The Diva Media

Board's RISC CPU is used to re-compress 1D-coded page data from the application to the format requested by

the opposite side (transmission) and to convert received data to 1D-coded page data that is sent to the

application (reception).

The re-compression process is handled internally by the board's RISC CPU and happens fully transparent to the

application that deals only with 1D (MH) coded data.

You can adjust the compression-related T.30 protocol settings via Global fax configuration options on page

44.

V.34 (33600 bps) fax support

The V.34 fax support can be activated via Global Dialogic® Diva® TTY configuration options on page 73. If

the Dialogic

Diva

Media Board is able to establish a connection with a transmission speed higher than 14400

bps (V.34), it handles this transparent to the application. In order to avoid incompatibility with FAX CLASS 2

applications, the Diva Media Board never indicates transmission speeds higher than 14400 bps to the

application. This means that transmission speeds higher than 14400 bps are mapped to 14400 bps.

You can use the "divalogd" accounting utility on page 89 that uses the Diva Media Board Management

interface on page 88 to get information on the real transmission speed and the used compression algorithm.