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C620 M100 M200 M500

Web User Interface


Phone User Interface


Text Configuration

sip_account.x.reliable_provisional_response_option = VALIDVALUE

XML Configuration (C620, M100, M200 only)


<idx id="x">





Sets the 100rel/PRACK option. Indicates if the reliable provisional responses are disabled, supported, or required.

1 (supported):

  • We will include "100rel" in "Supported" header.
  • This triggers the remote side (server or remote client) to include "Requires:100rel" in their response (180 or 183). Server may choose not to do so. But if it does, we need to respond with PRACK.
  • We will NOT include a "Requires: 100rel" in our requests (INVITE). i.e. we won't force anyone to use 100rel, but we will do if we were asked to do.

2 (required):

  • Everything as described for supported, plus our outgoing INVITE also includes "Requires: 100rel".
  • This forces the remote party must support 100rel.

Valid Values

0 (disabled), 1 (supported), 2 (required)

Default Value