# Ringing

As long as a station is on-hook, an application can cause it to ring. This topic describes:

- Starting ringing

- Stopping ringing

- Coordinating caller ID FSK with ring

## Starting ringing

To cause a station to ring, invoke cdiStartRing. In the invocation, pass a pointer to the CDI_RING_PARMS structure.

CX 2000 products are preconfigured with three different 6-second cadence types:

Preconfigured ring cadences for CX 2000 products

You can change one or more of these cadences. For more information, refer to the CX 2000 Installation and Developer's Manual or the CX 2000C Installation and Developer's Manual.

cdiStartRing cannot be invoked for a station while that station is ringing. If this function is invoked during an ongoing ring, CTAERR_FUNCTION_ACTIVE is returned.

## Stopping ringing

If enhanced mode is enabled, the DSP automatically stops station ringing when the station goes off-hook (CDIEVN_OFF_HOOK is returned). If enhanced mode is disabled, the application can invoke cdiStopRing to stop an ongoing ring.

If the station is off-hook and cdiStopRing is invoked, CTAERR_FUNCTION_NOT_ACTIVE is returned.

## Coordinating caller ID FSK with ring

CX boards can be configured to generate events that track ring cycles. The primary application for this is FSK caller ID generation. An application can determine when the first ring cycle is complete and can switch through and enable FSK generation on another resource board in the system to send caller ID between the first two ring cycles. Refer to cdiStartRing for more information.