NEC UNIVERGE SV9100 Features And Specifications page 721

telephone is placed on hold.
The system has the ability to receive DTMF information in SIP INFO messages sent by
Standard SIP terminals. This allows the SIP Terminal to initiate features during a ringing
state such as Camp-On and Message Waiting. SIP terminals must be able to support this
feature and have it enabled.
If Program 15-05-49 is set to 1: Allowed any time, SIP INFO is received upon arrival.
If Program 15-05-49 is set to 2: Allowed while RTP is not available, SIP INFO is received
while RTP is not established. An In-band method such as RFC2833 is used once the voice
path is established.
SIP INFO functions independently from other DTMF methods such as RFC2833. This
means SIP terminals should send DTMF information by a single method, otherwise the
system will receive both separately causing double digits.
NAT or NAPT is only supported on the DT800/DT700 series phones. NAT or NAPT is not
supported on the ML440, the Wireless DECT (SIP), or Softphone phones.
The SV9100 supports NAT for Standard SIP terminals.
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