Dynamic E911 delivers location information to PSAPs during emergency calls. Two methods available:
| Method | Use case | Location source |
|---|
| API-based addresses | Fixed locations (offices, buildings) | Pre-provisioned via API |
| GPS coordinates | Mobile devices, wearables, IoT | PIDF-LO in SIP INVITE |
API-based addresses
Pre-provision addresses and endpoints, then reference IDs in SIP headers during calls.
Dynamically provisioning emergency endpoints may result in a delay before the associated address is fully available for routing. Telnyx recommends pre-provisioning a persistent emergency address rather than relying on just-in-time provisioning.
In circumstances where an emergency call (e.g., 911) is initiated before a dynamically provisioned endpoint is fully activated, the call will be routed to a national emergency call center (PSAP) .
Create emergency address
POST /v2/dynamic_emergency_addresses
{
"house_number": "1901",
"street_pre_directional": "W",
"street_name": "MADISON",
"street_suffix": "ST",
"locality": "CHICAGO",
"administrative_area": "IL",
"postal_code": "60612",
"country_code": "US"
}
id - Address UUID for endpoint associationsip_geolocation_id - Include in Geolocation headerstatus - pending during validation, activated when ready
Create emergency endpoint
POST /v2/dynamic_emergency_endpoints
{
"dynamic_emergency_address_id": "uuid-from-address",
"callback_number": "+13125550000",
"caller_name": "Jane Doe"
}
sip_from_id - Include in From or P-Asserted-Identity header
Include both IDs in emergency call INVITE:
INVITE sip:911@sip.telnyx.com SIP/2.0
From: <sip:{sip_from_id}@origin.example.com>
To: <sip:911@sip.telnyx.com>
Geolocation: {sip_geolocation_id}
P-Asserted-Identity:
P-Asserted-Identity: <sip:{sip_from_id}@origin.example.com>
Geolocation: {sip_geolocation_id}
GPS coordinates (PIDF-LO)
Pass real-time coordinates in PIDF-LO format for mobile devices, wearables, and IoT.
| Parameter | Range | Notes |
|---|
| Latitude | -90 to +90 | Negative = South |
| Longitude | -180 to +180 | Negative = West |
| Precision | 6-8 decimal places | Meter-level accuracy |
INVITE sip:911@sip.telnyx.com SIP/2.0
From: <sip:+13125550100@sip.telnyx.com>
To: <sip:911@sip.telnyx.com>
Geolocation: <cid:location@example.com>
X-Latitude: latitude
X-Longitude: longitude
Content-Type: application/sdp
[SDP content]
INVITE sip:911@sip.telnyx.com SIP/2.0
From: <sip:+13125550100@sip.telnyx.com>
To: <sip:911@sip.telnyx.com>
Geolocation: <cid:location@example.com>
Content-Type: multipart/mixed;boundary=boundary1
--boundary1
Content-Type: application/sdp
[SDP content]
--boundary1
Content-Type: application/pidf+xml
Content-ID: <location@example.com>
<?xml version="1.0" encoding="UTF-8"?>
<presence xmlns="urn:ietf:params:xml:ns:pidf"
xmlns:gp="urn:ietf:params:xml:ns:pidf:geopriv10"
xmlns:gml="http://www.opengis.net/gml"
xmlns:dm="urn:ietf:params:xml:ns:pidf:data-model"
entity="sip:+13125550100@sip.telnyx.com">
<dm:device id="device-001">
<gp:geopriv>
<gp:location-info>
<gml:Point srsName="urn:ogc:def:crs:EPSG::4326">
<gml:pos>41.8781 -87.6298</gml:pos>
</gml:Point>
</gp:location-info>
<gp:usage-rules>
<gp:retransmission-allowed>false</gp:retransmission-allowed>
</gp:usage-rules>
</gp:geopriv>
<dm:timestamp>2024-01-15T10:30:00Z</dm:timestamp>
</dm:device>
</presence>
--boundary1--
Telnyx currently supports LIS and ASSIST as PIDF-LO methods.
Other methods are not supported.
PIDF-LO requirements
| Element | Requirement |
|---|
<gml:pos> | Latitude then longitude, space-separated |
srsName | Must be urn:ogc:def:crs:EPSG::4326 |
<dm:timestamp> | ISO 8601 format |
Testing
Use test number 933 to simulate emergency calls without dispatching services.
Address field limits
| Field | Required | Max Length | PIDF-LO Element |
|---|
| house_number | No | 6 | HNO |
| house_suffix | No | 45 | HNS |
| street_pre_directional | No | 2 | PRD |
| street_name | Yes | 200 | RD |
| street_suffix | No | 45 | STS |
| street_post_directional | No | 2 | POD |
| extended_address | No | 60* | LOC |
| locality | Yes | 100 | A3 |
| administrative_area | Yes | 2 | A1 |
| postal_code | Yes | 10 | PC |
| country_code | Yes | 2 | country |
| caller_name | No | 50 | - |
