# Calling Party Category (CPC)

Calling Party Category (**CPC**) identifies the type of network or device
from which a call originates, such as a landline, mobile network, or public
payphone. DIDWW can deliver CPC information on inbound SIP calls in the
Request-URI or as a parameter in the SIP **From** header.

Receiving systems can use CPC to route calls or apply different call handling
based on whether the call originated from a landline, mobile network, public
payphone, or an unknown source.

CPC delivery is disabled by default. To enable it, configure the inbound SIP
trunk for [CPC delivery in the Request-URI](#inbound-sip-cpc-uri-config) or request activation for [CPC delivery in
the From header](#inbound-sip-cpc-from-header). The selected method determines
which values are delivered and where the receiving system reads them.

## Delivery methods

| Method | Value format | Availability |
| --- | --- | --- |
| [Request-URI](#inbound-sip-cpc-uri) | Numeric values from `01` to `04` | Available for Toll-Free numbers only. Add the `{CALL_CPC}` variable to **User Part of R-URI** on the inbound SIP trunk. |
| [From header](#inbound-sip-cpc-from-header) | Text values such as `ordinary` and `cellular` | Requires activation by DIDWW Support at [support@didww.com](mailto:support%40didww.com). |

## CPC in the Request-URI

For Toll-Free calls, DIDWW can insert a two-digit CPC value into the user part
of the Request-URI. The position of `{CALL_CPC}` in **User Part of R-URI**
determines whether the value appears before or after the DID. The CPC value
always appears before the `@` symbol.

### Request-URI CPC values

| Value | Source type |
| --- | --- |
| `01` | Standard landline |
| `02` | Mobile network |
| `03` | Public payphone |
| `04` | Unclassified or unavailable source |

### Request-URI formats

The following formats place the CPC value after or before the DID:

```
{DID}{CALL_CPC}@example.com
{CALL_CPC}{DID}@example.com
```

For example, the following Request-URIs use DID `18003864279` and place the
CPC value after the DID:

```
Landline source: 1800386427901@example.com
Mobile source:   1800386427902@example.com
Payphone source: 1800386427903@example.com
Unknown source:  1800386427904@example.com
```

### Configure CPC in the Request-URI

To add the Calling Party Category value to the Request-URI:

1. Go to **Voice > Inbound Trunks** in the DIDWW User Panel.
2. Locate the inbound SIP trunk, click **Actions**, and select **Edit**.
3. On the **General** tab, include `{CALL_CPC}` in **User Part of R-URI**.
   Place it before or after `{DID}` according to the required Request-URI
   format. The field can also contain custom characters.
4. Click **Submit**.

If an inbound SIP trunk does not exist, [create a SIP trunk](../how-to-guides/create-sip-trunk.html) first. For the
complete field description,
see [Static Endpoint fields](../sip-trunk-settings-reference.html#inbound-sip-static-endpoint-fields).

[![Inbound SIP trunk General tab with CALL_CPC in User Part of R-URI](../../../../_images/cpc.png)](../../../../_images/cpc.png)


**Fig. 1.** Configure `{CALL_CPC}` in **User Part of R-URI**.

## CPC in the From header

DIDWW can deliver the CPC value as the `cpc` parameter in the SIP **From**
header. This method uses text values.

Note

CPC delivery in the **From** header is **not enabled by default**. To enable
this feature for your inbound SIP trunks, contact
[support@didww.com](mailto:support%40didww.com).

### From header CPC values

| Value | Source type |
| --- | --- |
| `ordinary` | Standard landline |
| `cellular` | Mobile network |
| `payphone` | Public payphone |
| `unknown` | Unclassified or unavailable source |

### From header format

The CPC value appears as a parameter in the SIP URI contained in the
**From** header:

```
From: <sip:{DID}@example.com;cpc=value>;tag=12345
```

For example, `cpc=ordinary` identifies a call from a standard landline:

```
From: <sip:14039351222@example.com;cpc=ordinary>;tag=12345
```

## Limitations

- Request-URI delivery is available for Toll-Free numbers only.
- From-header delivery is disabled by default and requires activation by
  DIDWW Support at [support@didww.com](mailto:support%40didww.com).
- DIDWW can deliver only the CPC information available for the incoming call.
  When the source category is unclassified or unavailable, DIDWW delivers
  `04` in the Request-URI or `unknown` in the **From** header.

## Related resources

- [Create a SIP trunk](../how-to-guides/create-sip-trunk.html)
- [Manage SIP trunks](../how-to-guides/manage-sip-trunks.html)
- [SIP trunk settings reference](../sip-trunk-settings-reference.html)

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