RFC 2833 (DTMF Digits) Dynamic Payload Negotiation

Overview

The SIP software supports RFC 2833 dynamic payload type negotiation between originating and terminating SIP gateways on a per call basis.

Pertinent Specification

RFC 2833

Description

The following applies to this feature:

• RFC 2833 is disabled by default. You should enable it before running calls.

• The SIP software supports RFC 2833 dynamic payload type negotiation in Session Description Protocol (SDP) within the SIP software.

• For outbound SIP Calls, the SIP software provides the RFC 2833 dynamic payload type in SDP as provided by the host application. If this information is not in the Outseize Control or Route Control messages, the SDP provides whatever was configured on the IP Network Interface Series 2 card.

• The host application can also provide the dynamic payload type for VoIP clear channel calls. It does not matter if the SIP software or the host application controls the calls.

• For in-bound SIP calls, the SIP software will propagate the RFC 2833 dynamic payload type to the IP Network Interface Series 2 card on a per connection basis.

• The SIP software can receive SIP RE-INVITE messages from the network that change the RFC 2833 dynamic payload type. The SIP software can not initiate a SIP RE-INVITE message to change RFC 2833 dynamic payload types.

• You can still configure the RFC 2833 Dynamic Payload Type when you configure the SIP software with the Resource Attribute Configure message (0x00E3).

API Messages

• Route Control (0x00E8)

• Outseize Control (0x002C)

Configuring

Follow the sections below to implement this feature in your host application.

Configuring the Default 2833 Payload Type on IPN Series 2

Use the following TLV to configure the default RFC 2833 Payload type on the Network Interface Series 2 cards.

Include the RFC 2833 Dynamic Payload Type TLV (0x01F1) in the Resource Attribute Configure message to configure the default payload type on a per module basis.

Changing the Default RFC 2833 Codec Value for Outbound Calls on IPN Series 2

Use the RFC 2833 Dynamic Payload Type TLV in the 0x001E PPL Generic ICB in either the Route Control or Outseize Control message to change the default RFC 2833 payload type.

Enabling or Disabling Digit Relay Enable

Use the RFC 2833 Enable TLV (0x01E2) in the 0x001E PPL Generic ICB in either the Outseize Control, Route Control, or Resource Attribute Configure message to enable or disable RFC 2833 support.

Querying Default RFC 2833 Payload Type

Use the VoIP Terminal Capabilities (0x01EA) TLV or the 0x01F1 RFC 2833 Dynamic Payload Type TLV in the Resource Attribute Query message to query the default RFC 2833 payload type configured for each module on the IP Network Interface Series 2 card.

Byte 12 in the VoIP Terminal Capabilities TLV indicates if the default value is supported and configurable.