# Connected line identification presentation (COLP)

The COLP service allows the calling party to receive a connected party's address information. The calling party can use this service to obtain the address information of the final connected party (the party causing the connect message transmission at the remote end). This information consists of:

- The calling party's national (ISDN) number

- The country code, and other international call information (if any)

- (Optional) Subaddress information, if provided by the connected party

This service is available under many variants, including Q.SIG.

## COLP under non-Q.SIG variants

Under most non-Q.SIG variants, the service is generally available to the calling user (no subscription is required).

The COLP supplementary service is activated and deactivated by the service provider. When the service is activated, the network automatically invokes the service on each outgoing call made by the calling user. The application need not perform any special activation or invocation operations to use the service.

The called user can present address information to the network in the ACU_CONN_RS primitive. If the called user does not include address information in the primitive, the network fills in the information by default.

### Macros for specifying address information

To specify address information, the called user uses the following macros:

Macro | Description
--- | ---
Acu_conn_rs_a_connected_nb | Pointer to buffer containing connected number.
Acu_conn_rs_connected_nb_size | Size of buffer containing connected number.
Acu_conn_rs_a_connected_sub | Pointer to buffer containing connected subaddress.
Acu_conn_rs_connected_sub_size | Size of buffer containing connected subaddress.
Acu_conn_rs_connected_nb_pres | Connected number presentation.
Acu_conn_rs_connected_nb_type | Connected number type.
Acu_conn_rs_connected_sub_odd_even | Connected subaddress odd/even.
Acu_conn_rs_connected_sub_type | Connected subaddress type.

The Acu_conn_rs_connected_nb_pres macro determines whether or not this information is to be made available to the calling user. If the calling user sets Acu_conn_rs_connected_nb_pres to N_PRES_ALLOWED, the calling user can access this information. If the called user sets Acu_conn_rs_connected_nb_pres to N_PRES_RESTRICTED, the network invokes the connected line presentation restriction (COLR) service, and blocks this information from the calling user. For more information about COLP, see Connected line identification restriction (COLR).

### Macros for accessing address information in the ACU_CONN_CO primitive

The calling user receives the address information in the ACU_CONN_CO primitive. To access this information, the called user uses the following macros:

Macro | Description
--- | ---
Acu_conn_co_a_connected_nb | Pointer to buffer containing connected number.
Acu_conn_co_connected_nb_size | Size of buffer containing connected number.
Acu_conn_co_a_connected_sub | Pointer to buffer containing connected subaddress.
Acu_conn_co_connected_sub_size | Size of buffer containing connected subaddress.
Acu_conn_co_connected_nb_pres | Connected number presentation.
Acu_conn_co_connected_nb_screen | Connected number screening indicator.
Acu_conn_co_connected_nb_type | Connected number type.
Acu_conn_co_connected_sub_odd_even | Connected subaddress odd/even.
Acu_conn_co_connected_sub_type | Connected subaddress type.

### Possible values for the screening macro

The Acu_conn_co_connected_nb_screen macro indicates the result of the network's screening of the address information. Screening is the process by which the network checks that the address information provided by the called user is acceptable to the network. Possible values for this macro are:

Value | Meaning
--- | ---
N_SCREEN_USER_PASSED | Number successfully screened.
N_SCREEN_USER_FAILED | Number not acceptable to the network.
N_SCREEN_NETWORK_PROVIDED | Number provided by the network (the calling user did not provide the information directly).
N_SCREEN_USER_PROVIDED | No screening took place.

## COLP under the Q.SIG variant

The Q.SIG application has the role of network. As a provider of the COLP service, the application is responsible for the following:

- Determining whether the called party address information is to be presented to the calling user depending upon the presentation setting.

- Sending the called party address information to the calling user.

- Screening the called party address information and providing the screening result in the primitive sent to the calling user.

## COLP and call forwarding services

If the forwarding user selects the option that the calling user is not notified of call forwarding, the calling user does not receive forwarding notification. In addition, the calling user does not receive COLP information when the call is answered unless the calling user has an override subscription option.

If the forwarding user selects the option that the calling user is notified, but without the forward-to number, the calling user does not receive COLP information when the call is answered unless the calling user has an override subscription option.