# Caller ID and CNAM OUT Caller ID and CNAM OUT control the calling number and caller name presented on outbound calls. Configure which Caller IDs an outbound trunk may use, choose how non-matching numbers are handled, and use the appropriate CNAM OUT delivery method. ## How outbound Caller ID works Caller ID, also called CLI (calling line identification), is the calling number that the originating SIP endpoint asks to present for an outbound call. The outbound trunk does not generate a Caller ID or automatically select one from **Allowed CLI(s)**. Your PBX, SBC, softphone, or other SIP endpoint must supply the number in every SIP `INVITE`. The calling number is placed in the user part of the SIP `From` header. For example: ``` From: ;tag=example ``` In this example, `12025550100` is the requested Caller ID. `caller.example` is the SIP URI domain and is not part of the calling number. Send the number in [E.164 format](routing-dialing/outbound-dialing.html#outbound-dialing). Before calls are sent, the trunk's [CLI Settings](outbound-trunk-reference.html#outbound-trunk-cli-settings) define which DIDWW numbers are treated as permitted Caller IDs. These settings validate the number supplied by the originating endpoint; they do not insert or replace it. ``` %%{init: { "theme": "base", "themeVariables": { "fontSize": "14px", "primaryColor": "#e0f2fe", "primaryBorderColor": "#38bdf8", "primaryTextColor": "#1f2d3d", "secondaryColor": "#ccfbf1", "secondaryBorderColor": "#2dd4bf", "secondaryTextColor": "#1f2d3d", "tertiaryColor": "#fef3c7", "tertiaryBorderColor": "#facc15", "tertiaryTextColor": "#1f2d3d", "lineColor": "#0066cc", "textColor": "#1f2d3d", "nodeTextColor": "#1f2d3d", "edgeLabelBackground": "#ffffff" } }}%% flowchart LR ORIGIN["Originating SIP endpoint
Send INVITE with Caller ID"] AUTH["Match and authenticate trunk"] READ["Read Caller ID
from From header"] CHECK{"Caller ID matches
permitted CLI?"} POLICY{"On CLI mismatch"} ROUTE["Select outbound route"] SEND["Send call downstream"] REJECT["Reject call"] ORIGIN --> AUTH --> READ --> CHECK CHECK -->|Match| ROUTE CHECK -->|No match| POLICY POLICY -->|Send Original CLI| ROUTE POLICY -->|Reject Call| REJECT ROUTE --> SEND classDef endpoint fill:#e0f2fe,stroke:#0066cc,color:#1f2d3d,stroke-width:1.5px classDef process fill:#ccfbf1,stroke:#2dd4bf,color:#1f2d3d,stroke-width:1.5px classDef decision fill:#fef3c7,stroke:#facc15,color:#1f2d3d,stroke-width:1.5px classDef rejected fill:#fee2e2,stroke:#f87171,color:#1f2d3d,stroke-width:1.5px class ORIGIN endpoint class AUTH,READ,ROUTE,SEND process class CHECK,POLICY decision class REJECT rejected linkStyle default stroke:#0066cc,stroke-width:1.5px ``` For each call, Caller ID is processed as follows: 1. **Send the Caller ID.** The originating SIP endpoint places the requested calling number in the SIP `From` header and sends the `INVITE`. 2. **Match and authenticate the trunk.** The SIP request is matched to an outbound trunk, and the originating system is authenticated. This confirms which system sent the request but does not validate the Caller ID. See [Authentication and security](authentication-security.html). 3. **Read the requested Caller ID.** The calling number is taken from the SIP `From` header of the authenticated request. 4. **Apply the CLI Settings.** The number is compared with the Caller IDs permitted by the matched trunk. If it matches, Caller ID validation succeeds. If it does not match, **On CLI mismatch** either forwards the original number or rejects the call. The trunk does not substitute another Caller ID. 5. **Select the route and send the call downstream.** If the call is not rejected, the destination, Caller ID, and available coverage determine the outbound route. A [local route](routing-dialing/outbound-dialing.html#outbound-dialing-local-routes) may be used when the destination and an eligible DIDWW Caller ID belong to the same country and in-country coverage is available. Otherwise, an available origin-based or international route may be used. CNAM OUT and [STIR/SHAKEN](stir-shaken-outbound.html) provide different information. CNAM OUT provides the caller name, while STIR/SHAKEN carries a signed identity assertion. Neither one supplies or replaces the Caller ID number. Note Passing Caller ID validation does not guarantee that the number will be displayed to the called party. The destination operator or an intermediate network may modify, suppress, or decline to display it according to its policies and applicable regulations. ### Allowed outbound CLIs The **Allow any DID(s) for Voice OUT** toggle determines which DIDWW numbers are treated as permitted CLIs: | Toggle state | Behavior | | --- | --- | | **Enabled** | All supported DIDWW numbers in your account are treated as permitted CLIs. Individual selection is not required. | | **Disabled** | Only numbers added to **Allowed CLI(s)** are treated as permitted. Select them from **Available CLI(s)**, which lists DIDWW numbers that support [local routes](routing-dialing/outbound-dialing.html#outbound-dialing-local-routes). DIDs without local-route support are not listed. | These settings define which numbers match the permitted CLI set. A non-matching number may still be forwarded when **On CLI mismatch** is set to **Send Original CLI**. For field values, defaults, and dependencies, see [CLI Settings](outbound-trunk-reference.html#outbound-trunk-cli-settings) in the Outbound trunk reference. ### CLI mismatch behavior A CLI mismatch occurs when the calling number in the SIP `From` header does not match the numbers permitted by the trunk's CLI Settings. This includes a third-party number or a DIDWW number that was not added to **Allowed CLI(s)** when **Allow any DID(s) for Voice OUT** is disabled. The trunk's **On CLI mismatch** setting determines the outcome: | Setting | Outcome | | --- | --- | | **Send Original CLI** | Forwards the original `From` header value downstream without modification. Display by the destination network is not guaranteed. | | **Reject Call** | Rejects the call when the calling number does not match the permitted CLI set. | CLI matching uses the calling number in the user part of the SIP `From` URI. It does not use the quoted display name, which is processed separately as CNAM OUT. Important **Send Original CLI** allows a non-matching number to be sent downstream. Use it only when presenting a third-party Caller ID intentionally and when you are authorized to use that number. To restrict every call to the permitted DIDWW Caller IDs, select **Reject Call**. --- ## CNAM OUT CNAM OUT provides caller name information for outbound calls. Caller ID identifies the calling number, while CNAM OUT provides a name that may be displayed alongside it. CNAM OUT does not create, validate, or replace the Caller ID number. DIDWW supports two CNAM OUT delivery methods: CNAM OUT registration for supported US DIDWW numbers, and a per-call SIP `From` display name for Canadian and other non-US caller IDs. The applicable method depends on the Caller ID and whether the name is registered in advance or supplied in each call. ## How CNAM OUT works Select the supported method for the Caller ID, then follow its setup and delivery process: ``` %%{init: { "theme": "base", "themeVariables": { "fontSize": "14px", "primaryColor": "#e0f2fe", "primaryBorderColor": "#38bdf8", "primaryTextColor": "#1f2d3d", "secondaryColor": "#ccfbf1", "secondaryBorderColor": "#2dd4bf", "secondaryTextColor": "#1f2d3d", "tertiaryColor": "#fef3c7", "tertiaryBorderColor": "#facc15", "tertiaryTextColor": "#1f2d3d", "lineColor": "#0066cc", "textColor": "#1f2d3d", "nodeTextColor": "#1f2d3d", "edgeLabelBackground": "#ffffff" } }}%% flowchart LR START["Caller name for an outbound call"] METHOD{"Which CNAM OUT
method applies?"} REGISTER["Supported US DIDWW number
Register name and Identity in My Numbers"] ACTIVE["Registration is reviewed
CNAM OUT status becomes Active"] DB_CALL["Send call using the DID
as Caller ID"] LOOKUP["Destination operator
query the registered CNAM"] HEADER["Non-US or third-party Caller ID
Add CNAM to SIP From for each INVITE"] RELAY["Relay caller name when
available and supported"] DISPLAY["Destination display
the caller name"] START --> METHOD METHOD -->|CNAM registration| REGISTER REGISTER --> ACTIVE ACTIVE --> DB_CALL DB_CALL --> LOOKUP LOOKUP --> DISPLAY METHOD -->|SIP From header| HEADER HEADER --> RELAY RELAY --> DISPLAY classDef endpoint fill:#e0f2fe,stroke:#0066cc,color:#1f2d3d,stroke-width:1.5px classDef process fill:#ccfbf1,stroke:#2dd4bf,color:#1f2d3d,stroke-width:1.5px classDef decision fill:#fef3c7,stroke:#facc15,color:#1f2d3d,stroke-width:1.5px classDef result fill:#ccfbf1,stroke:#2dd4bf,color:#1f2d3d,stroke-width:1.5px class START endpoint class METHOD,LOOKUP decision class REGISTER,ACTIVE,DB_CALL,HEADER,RELAY process class DISPLAY result linkStyle default stroke:#0066cc,stroke-width:1.5px ``` ### Registered CNAM OUT CNAM OUT registration is available for DIDWW US numbers that support the CNAM OUT feature. It is configured on the DID number in **Phone Numbers > My Numbers**, rather than on the outbound trunk. Use [Manage CNAM OUT](../../phone-numbers/my-numbers/how-to-guides/configure-cnam-out.html) to submit a caller name of up to 15 characters and select the required Identity. The request is reviewed, usually within 48-72 hours. The registered value becomes available for downstream lookup when the DID's [CNAM OUT status](../../phone-numbers/my-numbers/my-numbers-reference.html#my-numbers-cnam-out-statuses) is **Active**. When an outbound call presents the DID as its Caller ID, the destination operator may use that DID number to query registered CNAM. If the operator performs the lookup and retrieves the registered value, it can display the caller name to the called party. ### SIP From header CNAM OUT For Canadian and other non-US caller IDs, place the caller name in the display-name portion of the SIP `From` header of every `INVITE`. This method is also useful when a per-call value is required or when a non-US third-party Caller ID cannot use the database-registration method. DIDWW does not have access to a Canadian CNAM database equivalent to the CNAM database used for US numbers, so this method does not use the US database-registration workflow. Send the `INVITE` to a [DIDWW outbound signaling endpoint](outbound-sip-information.html#voice-out-signaling-endpoints). DIDWW relays the caller name to downstream carriers when available and supported. Place the CNAM value as a quoted display name before the SIP URI: ``` From: "Example Name" ;tag=example ``` In this example: - `Example Name` is the caller name relayed for this call. - `12025550100` is the Caller ID in E.164 format. - `caller.example` is the SIP URI domain and is not part of the caller name or Caller ID. Note The caller name must not exceed 15 characters. Avoid special characters that intermediate SIP systems may alter or remove. Important Neither CNAM OUT method guarantees that the caller name will be displayed. With database registration, the destination operator must perform a lookup. With the SIP-header method, intermediate and destination networks must preserve and support the display-name value. ## Related resources - [Outbound dialing](routing-dialing/outbound-dialing.html) - Format destination numbers and understand local-route selection. - [Caller Name Delivery (CNAM)](../cnam/index.html#user-panel-cnam) - Compare CNAM IN and CNAM OUT. On this page