Media5 Mediatrix 4104, Reference Manual

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T.38 Fax Reference Manual (SIP Version)
Mediatrix 4104 253
2. Set the number of redundancy packets sent with the current packet in the
dataIfCodecT38ProtectionLevel variable.
This is the standard redundancy offered by T.38. Please see step 3 for additional reliability options
for T.38.
Available values range from 1 to 5, 3 being the default value.
3. For additional reliability, define the number of times T.38 packets are retransmitted in the
dataIfT38FinalFramesRedundancy variable.
This only applies to the T.38 packets where the PrimaryUDPTL contains the following T.38 data
type:
• HDLC_SIG_END,
• HDLC_FCS_OK_SIG_END,
• HDLC_FCS_BAD_SIG_END and
• T4_NON_ECM_SIG_END
4. Restart the Mediatrix 4104 so that the changes may take effect.
T.38 No-Signal
You can set the Mediatrix 4104 to send no-signal packets during a T.38 fax transmission. The Mediatrix 4104
sends no-signal packets if no meaningful data have been sent for a user-specified period of time.

To send T.38 no-signal:
1. Set the period, in seconds, at which no-signal packets are sent during a T.38 transmission in the
dataIfT38NoSignalTimeout variable.
No-signal packets are sent out if there are no valid data to send.
2. Enable the sending of T.38 no-signal packets by setting the dataIfT38NoSignalEnable variable to
enable .
Behaviour when Switching from Voice to T.38
You can define the behaviour when the unit starts sending T.38 no-signal packets when being Re-Invited to
switch from voice to T.38.

To define the behaviour:
1. In the sipInteropMIB , set the sipInteropT38NoSignalBehavior variable to the proper value.
This configuration has no effect if the dataIfT38NoSignalEnable variable is set to disable (see “T.38
No-Signal” on page 253 for more details).
Figure 83: Behaviour when Switching from Voice to T.38 Parameters
Parameter Description
receivingReInvite The unit starts sending T.38 no-signal packets when receiving the Re-Invite.
receivingAck The unit waits until the ACK to its 200 OK has been received before sending
T.38 no-signal packets.