AudioCodes MEDIAPACK VERSION 6.2 - Manual (Page 39)

Version 6.2 39 December 2010
SIP Release Notes 1. What's New in Release 6.2
23. Fax Transmission behind NAT:
Product
MP-11x MP-124
Mediant 600 Mediant 1000
Mediant 800 MSBG Mediant 1000 MSBG
Mediant 2000
Mediant 3000/TP-6310 Mediant 3000 HA/TP-6310
Mediant 3000/TP-8410 Mediant 3000 HA/TP-8410
Management Protocol
Web INI SNMP EMS CLI
This feature provides support for transmission from fax machines (connected to the
device) located inside a Network Address Translation (NAT). Generally, the firewall
blocks T.38 (and other) packets received from the WAN, unless the device behind the
NAT sends at least one IP packet from the LAN to the WAN through the firewall. If the
firewall blocks T.38 packets sent from the termination IP fax, the fax fails.
To overcome this, the device sends No-Op (“no-signal”) packets to open a pinhole in
the NAT for the answering fax machine. The originating fax does not wait for an
answer, but immediately starts sending T.38 packets to the terminating fax machine.
This feature is enabled using the new parameter, T38FaxSessionImmediateStart. The
No-Op packets are enabled using the existing NoOpEnable and NoOpInterval
parameters.
24. Euro-ISDN Message Waiting Indication (MWI) for IP-to-Tel Calls:
Product
MP-11x MP-124
Mediant 600 Mediant 1000
Mediant 800 MSBG Mediant 1000 MSBG
Mediant 2000
Mediant 3000/TP-6310 Mediant 3000 HA/TP-6310
Mediant 3000/TP-8410 Mediant 3000 HA/TP-8410
Management Protocol
Web INI SNMP EMS CLI
This feature provides support for Euro-ISDN MWI for IP-to-Tel calls. The device
interworks SIP MWI NOTIFY messages to Euro-ISDN Facility information element (IE)
MWI messages. This is supported by the existing VoiceMailInterface parameter (set to
8).