We provide our customers with the ability to enable certain features on their SIP Connection, to allow for more control on your inbound or outbound calls.
If you are looking for a detailed overview of the basic settings, please review this article for more information.
Inbound SIP Settings
The settings available are as follows:
Number Format (DNIS / ANI) - This setting controls the number format in the FROM/TO and INVITE URI - described in further detail here. Useful for when your system only supports a particular number format on inbound rules.
No Ringback Timeout - This setting controls how long Telnyx will wait for your SIP 180/183 response before terminating the call. By default, this timeout is set to 5 seconds.
No Answer Timeout - This setting controls how long Telnyx will wait for your SIP 200 OK response before terminating the call. By default, this timeout is set to 300 seconds.
Channel Limit - This setting controls how many concurrent calls are allowed at any one time. By default, there is no limit specified meaning if you receive X amount of calls to DID's associated with this SIP Connection, we will process all requests.
Receive SIP URI Calls - This setting is only available on credential type SIP Connections and allows Telnyx to process calls where your sip:email@example.com is dialed. This can be disabled, set to be allow from anyone or just from your connections.
Encrypted Media - This setting allows for the media of your inbound calls to be encrypted either with ZRTP or SRTP. When enabled, Telnyx will send the SIP INVITE to your connection with crypto media attributes in order to establish end-to-end media encryption between our media servers and your phone system.
Offered Audio / Video Codecs - This setting allows you to enable the codecs which you prefer to be used and in order of preference.
Enable SIP Compact Headers - This setting, when enabled, means that Telnyx will send the SIP INVITE to your Connection with the SIP headers compacted. Ideal for reducing Bandwidth consumption.
Enable 3rd Party Call Control - Specifically for Cisco UCM devices but useful in cases where the SIP INVITE doesn't include a SDP (late media negotiation).
Enable Privacy Zone - This setting controls where we hide the anonymous details of a caller on an inbound call. When not enabled, we will anonymize the From and the PAID headers. If you are a direct end user, and you want to make sure anonymity is maintained, please keep it disabled. If the setting is enabled, Telnyx will indicate the same Privacy value as received from the caller, but send caller Name and Number in the From and PAID headers.
Enable Prack - This setting, when enabled, will allow for an acknowledgment system for your provisional 1XX responses. Each time you send back a 1XX, we will send back a SIP PRACK acknowledgment. By default, the setting is not enabled.
Receive ISUP Headers into SIP Headers - Sometimes our inbound PSTN carriers can send SS7 PSTN ISUP information as mime content type in the body of the SIP INVITE. By default, we pass this information along but if your system has difficulty parsing ISUP headers, you can enable this feature to ensure the ISUP is converted into the appropriate SIP Headers instead.
Generate Ringback Tone - This setting, when enabled, means Telnyx will immediately send ringback to our upstream carriers to indicate that the destination is ringing. Ideal for cases where certain end devices can't produce automatic ringback.
Outbound SIP Settings
The settings available are as follows:
Caller ID Override - Users have a choice of always overriding the caller ID for all outbound calls, overriding the caller ID for normal calls or overriding the caller ID for emergency calls. Example, if you have "Emergency Only" enabled with the caller ID you prefer, and a caller dials 911, we'll make sure to convert the caller ID provided in your SIP INVITE to the one defined your SIP Connection.
Localization Country - This setting, when enabled, will allow the user to dial out with the associated exit code of that country and allow the user to dial local numbers of that country also, without having the include the exit + country code. When a country is not specified, Telnyx will attempt to validate the dialed numbers as US and if that validation fails, a 404 invalid destination response is returned.
Channel Limit - When specified, Telnyx will honour the channel limit and not process any more concurrent calls beyond that. The user will receive a 403 channel limit reached response.
T.38 Reinvite Initiated By - Specifically for fax machines sending outbound faxes. By default the setting is disabled. However, users can choose either "Customer" or "Telnyx" to initiate the SIP reINVITE for T.38 depending on their use case.
Outbound Voice Profile - The user can choose which outbound profile the SIP Connection can be associated with.
Encrypted Media - This setting allows for the media of your outbound calls to be encrypted either with ZRTP or SRTP. When enabled, Telnyx expects to receive your SIP INVITE from your connection with crypto media attributes in order to establish end-to-end media encryption between our media servers and your phone system.
Enable Instant Ringback - When enabled, this allows us to passthrough any remote ringback from the end devices in the form of a SIP 183 with SDP.
Generate Ringback Tone - When enabled, this allows us to generate ringback even though the end destination may not be ringing yet.