2.2 Programming

Jitter buffer Settings (G.711 for Fax)

Parameter

Default

Value Range

 

 

 

Jitter Buffer Minimum (ms)

50

10 × n (n = 4–10)

 

 

 

Jitter Buffer Maximum (ms)

500

10 × n (n = 4–50)

 

 

 

CODEC Frame Settings

The parameters below are used to set the interval between packet transmissions for each type of CODEC. It is recommended that all VoIP Gateway Cards in a VoIP network have the same settings for these parameters.

For details, refer to "Detailed Explanations".

Parameter

Default

Value Range

 

 

 

G.723.1 Packet Sending Interval (ms)

30

30, 60, 90

 

 

 

G.729A Packet Sending Interval (ms)

20

20, 30, 40, 60

 

 

 

G.711 Packet Sending Interval (ms)

20

20, 30, 40, 60

 

 

 

Echo Canceller Settings

 

 

 

 

 

Parameter & Description

Default

Value Range

 

 

 

Echo Canceller

48

48, 128, Don't use

Specifies the length of the echo canceller (in milliseconds)

 

 

when using the echo cancellation feature (G.168), or disables

 

 

the feature.

 

 

Echo is the audible duplication of a caller's voice on the return

 

 

path; when echo exists, the caller hears his or her own voice

 

 

after some delay. The echo canceller eliminates this echo.

 

 

Generally, the default length of 48 ms will suffice. However, if

 

 

an echo is still heard, it is recommended that you set the

 

 

length to 128 ms.

 

 

Note

 

 

There are various factors that may cause an echo. In

 

 

some cases, this feature does not eliminate the echo

 

 

entirely.

 

 

 

 

 

20 Programming Guide